mwi.c

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/*
 * Asterisk -- An open source telephony toolkit.
 *
 * Copyright (C) 2019, Sangoma Technologies Corporation
 *
 * Kevin Harwell <kharwell@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.
 */
 
/*** MODULEINFO
    <support_level>core</support_level>
 ***/
 
#include "asterisk.h"
 
#include "asterisk/app.h"
#include "asterisk/mwi.h"
#include "asterisk/stasis_channels.h"
 
/*!
 * \brief Define \ref stasis topic objects
 * @{
 */
static struct stasis_state_manager *mwi_state_manager;
static struct stasis_cache *mwi_state_cache;
static struct stasis_caching_topic *mwi_topic_cached;
 
/*! @} */
 
/*! \brief Convert a MWI \ref stasis_message to a \ref ast_event */
static struct ast_event *mwi_to_event(struct stasis_message *message)
{
    struct ast_event *event;
    struct ast_mwi_state *mwi_state;
    char *mailbox;
    char *context;
 
    if (!message) {
        return NULL;
    }
 
    mwi_state = stasis_message_data(message);
 
    /* Strip off @context */
    context = mailbox = ast_strdupa(mwi_state->uniqueid);
    strsep(&context, "@");
    if (ast_strlen_zero(context)) {
        context = "default";
    }
 
    event = ast_event_new(AST_EVENT_MWI,
                AST_EVENT_IE_MAILBOX, AST_EVENT_IE_PLTYPE_STR, mailbox,
                AST_EVENT_IE_CONTEXT, AST_EVENT_IE_PLTYPE_STR, context,
                AST_EVENT_IE_NEWMSGS, AST_EVENT_IE_PLTYPE_UINT, mwi_state->new_msgs,
                AST_EVENT_IE_OLDMSGS, AST_EVENT_IE_PLTYPE_UINT, mwi_state->old_msgs,
                AST_EVENT_IE_EID, AST_EVENT_IE_PLTYPE_RAW, &mwi_state->eid, sizeof(mwi_state->eid),
                AST_EVENT_IE_END);
 
    return event;
}
 
/*!
 * \brief Define \ref stasis message types for MWI
 * @{
 */
STASIS_MESSAGE_TYPE_DEFN(ast_mwi_state_type,
    .to_event = mwi_to_event, );
STASIS_MESSAGE_TYPE_DEFN(ast_mwi_vm_app_type);
 
/*! @} */
 
static void mwi_state_dtor(void *obj)
{
    struct ast_mwi_state *mwi_state = obj;
    ast_string_field_free_memory(mwi_state);
    ao2_cleanup(mwi_state->snapshot);
    mwi_state->snapshot = NULL;
}
 
struct stasis_topic *ast_mwi_topic_all(void)
{
    return stasis_state_all_topic(mwi_state_manager);
}
 
struct stasis_cache *ast_mwi_state_cache(void)
{
    return mwi_state_cache;
}
 
struct stasis_topic *ast_mwi_topic_cached(void)
{
    return stasis_caching_get_topic(mwi_topic_cached);
}
 
struct stasis_topic *ast_mwi_topic(const char *uniqueid)
{
    return stasis_state_topic(mwi_state_manager, uniqueid);
}
 
static struct ast_mwi_state *mwi_create_state(const char *mailbox, const char *context,
    int urgent_msgs, int new_msgs, int old_msgs)
{
    struct ast_mwi_state *mwi_state;
 
    ast_assert(!ast_strlen_zero(mailbox));
 
    mwi_state = ao2_alloc(sizeof(*mwi_state), mwi_state_dtor);
    if (!mwi_state) {
        ast_log(LOG_ERROR, "Unable to create MWI state for mailbox '%s@%s'\n",
                mailbox, ast_strlen_zero(context) ? "" : context);
        return NULL;
    }
 
    if (ast_string_field_init(mwi_state, 256)) {
        ast_log(LOG_ERROR, "Unable to initialize MWI state for mailbox '%s@%s'\n",
                mailbox, ast_strlen_zero(context) ? "" : context);
        ao2_ref(mwi_state, -1);
        return NULL;
    }
    if (!ast_strlen_zero(context)) {
        ast_string_field_build(mwi_state, uniqueid, "%s@%s", mailbox, context);
    } else {
        ast_string_field_set(mwi_state, uniqueid, mailbox);
    }
 
    mwi_state->urgent_msgs = urgent_msgs;
    mwi_state->new_msgs = new_msgs;
    mwi_state->old_msgs = old_msgs;
 
    return mwi_state;
}
 
static struct ast_mwi_state *mwi_retrieve_then_create_state(const char *mailbox)
{
    int urgent_msgs;
    int new_msgs;
    int old_msgs;
 
    ast_app_inboxcount2(mailbox, &urgent_msgs, &new_msgs, &old_msgs);
    return mwi_create_state(mailbox, NULL, urgent_msgs, new_msgs, old_msgs);
}
 
struct ast_mwi_state *ast_mwi_create(const char *mailbox, const char *context)
{
    return mwi_create_state(mailbox, context, 0, 0, 0);
}
 
/*!
 * \internal
 * \brief Create a MWI state snapshot message.
 * \since 12.2.0
 *
 * \param[in] mailbox The mailbox identifier string.
 * \param[in] context The context this mailbox resides in (NULL or "" if only using mailbox)
 * \param urgent_msgs
 * \param[in] new_msgs The number of new messages in this mailbox
 * \param[in] old_msgs The number of old messages in this mailbox
 * \param[in] channel_id A unique identifier for a channel associated with this
 * change in mailbox state
 * \param[in] eid The EID of the server that originally published the message
 *
 * \return message on success.  Use ao2_cleanup() when done with it.
 * \retval NULL on error.
 */
static struct stasis_message *mwi_state_create_message(
    const char *mailbox,
    const char *context,
    int urgent_msgs,
    int new_msgs,
    int old_msgs,
    const char *channel_id,
    struct ast_eid *eid)
{
    struct ast_mwi_state *mwi_state;
    struct stasis_message *message;
 
    if (!ast_mwi_state_type()) {
        return NULL;
    }
 
    mwi_state = mwi_create_state(mailbox, context, urgent_msgs, new_msgs, old_msgs);
    if (!mwi_state) {
        return NULL;
    }
 
    if (!ast_strlen_zero(channel_id)) {
        mwi_state->snapshot = ast_channel_snapshot_get_latest(channel_id);
    }
 
    if (eid) {
        mwi_state->eid = *eid;
    } else {
        mwi_state->eid = ast_eid_default;
    }
 
    /*
     * XXX As far as stasis is concerned, all MWI events are local.
     *
     * We may in the future want to make MWI aggregate local/remote
     * message counts similar to how device state aggregates state.
     */
    message = stasis_message_create_full(ast_mwi_state_type(), mwi_state, &ast_eid_default);
    ao2_cleanup(mwi_state);
    return message;
}
 
/*!
 * \internal
 *
 * This object currently acts as a typedef, but can also be thought of as a "child" object
 * of the stasis_state_subscriber type. As such the "base" pointer should always be the
 * first object attribute. Doing so allows this object to be easily type cast and used by
 * the stasis_state code.
 */
struct ast_mwi_subscriber {
    /*! The "base" state subscriber. (Must be first object attribute) */
    struct stasis_state_subscriber *base;
};
 
struct ast_mwi_subscriber *ast_mwi_add_subscriber(const char *mailbox)
{
    return (struct ast_mwi_subscriber *)stasis_state_add_subscriber(
        mwi_state_manager, mailbox);
}
 
struct ast_mwi_subscriber *ast_mwi_subscribe_pool(const char *mailbox,
    stasis_subscription_cb callback, void *data)
{
    struct stasis_subscription *stasis_sub;
    struct ast_mwi_subscriber *sub = (struct ast_mwi_subscriber *)stasis_state_subscribe_pool(
        mwi_state_manager, mailbox, callback, data);
 
    if (!sub) {
        return NULL;
    }
 
    stasis_sub = ast_mwi_subscriber_subscription(sub);
 
    stasis_subscription_accept_message_type(stasis_sub, ast_mwi_state_type());
    stasis_subscription_set_filter(stasis_sub, STASIS_SUBSCRIPTION_FILTER_SELECTIVE);
 
    return sub;
}
 
void *ast_mwi_unsubscribe(struct ast_mwi_subscriber *sub)
{
    return stasis_state_unsubscribe((struct stasis_state_subscriber *)sub);
}
 
void *ast_mwi_unsubscribe_and_join(struct ast_mwi_subscriber *sub)
{
    return stasis_state_unsubscribe_and_join((struct stasis_state_subscriber *)sub);
}
 
struct stasis_topic *ast_mwi_subscriber_topic(struct ast_mwi_subscriber *sub)
{
    return stasis_state_subscriber_topic((struct stasis_state_subscriber *)sub);
}
 
struct ast_mwi_state *ast_mwi_subscriber_data(struct ast_mwi_subscriber *sub)
{
    struct stasis_state_subscriber *s = (struct stasis_state_subscriber *)sub;
    struct ast_mwi_state *mwi_state = stasis_state_subscriber_data(s);
 
    return mwi_state ?: mwi_retrieve_then_create_state(stasis_state_subscriber_id(s));
}
 
struct stasis_subscription *ast_mwi_subscriber_subscription(struct ast_mwi_subscriber *sub)
{
    return stasis_state_subscriber_subscription((struct stasis_state_subscriber *)sub);
}
 
/*!
 * \internal
 *
 * This object currently acts as a typedef, but can also be thought of as a "child" object
 * of the stasis_state_publisher type. As such the "base" pointer should always be the
 * first object attribute. Doing so allows this object to be easily type cast and used by
 * the stasis_state code.
 */
struct ast_mwi_publisher {
    /*! The "base" state publisher. (Must be first object attribute) */
    struct stasis_state_publisher *base;
};
 
struct ast_mwi_publisher *ast_mwi_add_publisher(const char *mailbox)
{
    return (struct ast_mwi_publisher *)stasis_state_add_publisher(
        mwi_state_manager, mailbox);
}
 
int ast_mwi_add_observer(struct ast_mwi_observer *observer)
{
    return stasis_state_add_observer(mwi_state_manager,
        (struct stasis_state_observer *)observer);
}
 
void ast_mwi_remove_observer(struct ast_mwi_observer *observer)
{
    stasis_state_remove_observer(mwi_state_manager,
        (struct stasis_state_observer *)observer);
}
 
struct mwi_handler_data {
    on_mwi_state handler;
    void *data;
};
 
static int handle_mwi_state(const char *id, struct stasis_message *msg, void *user_data)
{
    struct mwi_handler_data *d = user_data;
    struct ast_mwi_state *mwi_state = stasis_message_data(msg);
    int res;
 
    if (mwi_state) {
        return d->handler(mwi_state, d->data);
    }
 
    mwi_state = mwi_create_state(id, NULL, 0, 0, 0);
    if (!mwi_state) {
        return 0;
    }
 
    res = d->handler(mwi_state, d->data);
    ao2_ref(mwi_state, -1);
    return res;
}
 
void ast_mwi_state_callback_all(on_mwi_state handler, void *data)
{
    struct mwi_handler_data d = {
        .handler = handler,
        .data = data
    };
 
    stasis_state_callback_all(mwi_state_manager, handle_mwi_state, &d);
}
 
void ast_mwi_state_callback_subscribed(on_mwi_state handler, void *data)
{
    struct mwi_handler_data d = {
        .handler = handler,
        .data = data
    };
 
    stasis_state_callback_subscribed(mwi_state_manager, handle_mwi_state, &d);
}
 
int ast_mwi_publish(struct ast_mwi_publisher *pub, int urgent_msgs,
    int new_msgs, int old_msgs, const char *channel_id, struct ast_eid *eid)
{
    struct stasis_state_publisher *p = (struct stasis_state_publisher *)pub;
    struct stasis_message *msg = mwi_state_create_message(stasis_state_publisher_id(p),
        NULL, urgent_msgs, new_msgs, old_msgs, channel_id, eid);
 
    if (!msg) {
        return -1;
    }
 
    stasis_state_publish(p, msg);
    ao2_ref(msg, -1);
 
    return 0;
}
 
int ast_mwi_publish_by_mailbox(const char *mailbox, const char *context, int urgent_msgs,
    int new_msgs, int old_msgs, const char *channel_id, struct ast_eid *eid)
{
    struct ast_mwi_state *mwi_state;
    struct stasis_message *msg = mwi_state_create_message(
        mailbox, context, urgent_msgs, new_msgs, old_msgs, channel_id, eid);
 
    if (!msg) {
        return -1;
    }
 
    mwi_state = stasis_message_data(msg);
    stasis_state_publish_by_id(mwi_state_manager, mwi_state->uniqueid, NULL, msg);
    ao2_ref(msg, -1);
 
    return 0;
}
 
int ast_publish_mwi_state_full(
    const char *mailbox,
    const char *context,
    int new_msgs,
    int old_msgs,
    const char *channel_id,
    struct ast_eid *eid)
{
    return ast_mwi_publish_by_mailbox(mailbox, context, 0, new_msgs, old_msgs, channel_id, eid);
}
 
int ast_delete_mwi_state_full(const char *mailbox, const char *context, struct ast_eid *eid)
{
    RAII_VAR(struct stasis_message *, msg, NULL, ao2_cleanup);
    struct stasis_message *cached_msg;
    struct stasis_message *clear_msg;
    struct ast_mwi_state *mwi_state;
 
    msg = mwi_state_create_message(mailbox, context, 0, 0, 0, NULL, eid);
    if (!msg) {
        return -1;
    }
 
    mwi_state = stasis_message_data(msg);
 
    /*
     * XXX As far as stasis is concerned, all MWI events are local.
     *
     * For now, it is assumed that there is only one entity
     * maintaining the state of a particular mailbox.
     *
     * If we ever have multiple MWI event entities maintaining
     * the same mailbox that wish to delete their cached entry
     * we will need to do something about the race condition
     * potential between checking the cache and removing the
     * cache entry.
     */
    cached_msg = stasis_cache_get_by_eid(ast_mwi_state_cache(),
        ast_mwi_state_type(), mwi_state->uniqueid, &ast_eid_default);
    if (!cached_msg) {
        /* Nothing to clear from the cache, but still need to remove state */
        stasis_state_remove_publish_by_id(mwi_state_manager, mwi_state->uniqueid, eid, NULL);
        return -1;
    }
    ao2_cleanup(cached_msg);
 
    clear_msg = stasis_cache_clear_create(msg);
    stasis_state_remove_publish_by_id(mwi_state_manager, mwi_state->uniqueid, eid, clear_msg);
    ao2_cleanup(clear_msg);
 
    return 0;
}
 
static const char *mwi_state_get_id(struct stasis_message *message)
{
    if (ast_mwi_state_type() == stasis_message_type(message)) {
        struct ast_mwi_state *mwi_state = stasis_message_data(message);
        return mwi_state->uniqueid;
    } else if (stasis_subscription_change_type() == stasis_message_type(message)) {
        struct stasis_subscription_change *change = stasis_message_data(message);
        return change->uniqueid;
    }
 
    return NULL;
}
 
static void mwi_blob_dtor(void *obj)
{
    struct ast_mwi_blob *mwi_blob = obj;
 
    ao2_cleanup(mwi_blob->mwi_state);
    ast_json_unref(mwi_blob->blob);
}
 
struct stasis_message *ast_mwi_blob_create(struct ast_mwi_state *mwi_state,
                           struct stasis_message_type *message_type,
                           struct ast_json *blob)
{
    struct ast_mwi_blob *obj;
    struct stasis_message *msg;
 
    ast_assert(blob != NULL);
 
    if (!message_type) {
        return NULL;
    }
 
    obj = ao2_alloc(sizeof(*obj), mwi_blob_dtor);
    if (!obj) {
        return NULL;
    }
 
    obj->mwi_state = mwi_state;
    ao2_ref(obj->mwi_state, +1);
    obj->blob = ast_json_ref(blob);
 
    /* This is not a normal MWI event.  Only used by the MinivmNotify app. */
    msg = stasis_message_create(message_type, obj);
    ao2_ref(obj, -1);
 
    return msg;
}
 
static void mwi_cleanup(void)
{
    ao2_cleanup(mwi_state_cache);
    mwi_state_cache = NULL;
    mwi_topic_cached = stasis_caching_unsubscribe_and_join(mwi_topic_cached);
    ao2_cleanup(mwi_state_manager);
    mwi_state_manager = NULL;
    STASIS_MESSAGE_TYPE_CLEANUP(ast_mwi_state_type);
    STASIS_MESSAGE_TYPE_CLEANUP(ast_mwi_vm_app_type);
}
 
int mwi_init(void)
{
    ast_register_cleanup(mwi_cleanup);
 
    if (STASIS_MESSAGE_TYPE_INIT(ast_mwi_state_type) != 0) {
        return -1;
    }
 
    if (STASIS_MESSAGE_TYPE_INIT(ast_mwi_vm_app_type) != 0) {
        return -1;
    }
 
    mwi_state_manager = stasis_state_manager_create("mwi:all");
    if (!mwi_state_manager) {
        return -1;
    }
 
    mwi_state_cache = stasis_cache_create(mwi_state_get_id);
    if (!mwi_state_cache) {
        return -1;
    }
 
    mwi_topic_cached = stasis_caching_topic_create(ast_mwi_topic_all(), mwi_state_cache);
    if (!mwi_topic_cached) {
        return -1;
    }
 
    return 0;
}