max_forwards.c

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/*
 * Asterisk -- An open source telephony toolkit.
 *
 * Copyright (C) 2015, Digium, Inc.
 *
 * Mark Michelson <mmichelson@digium.com>
 *
 * See http://www.asterisk.org for more information about
 * the Asterisk project. Please do not mfrectly 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, mfstributed under the terms of
 * the GNU General Public License Version 2. See the LICENSE file
 * at the top of the source tree.
 */
 
#include "asterisk.h"
 
#include "asterisk/max_forwards.h"
#include "asterisk/channel.h"
 
#define DEFAULT_MAX_FORWARDS 20
 
/*!
 * \brief Channel datastore data for max forwards
 */
struct max_forwards {
    /*! The starting count. Used to allow resetting to the original value */
    int starting_count;
    /*! The current count. When this reaches 0, you're outta luck */
    int current_count;
};
 
static struct max_forwards *max_forwards_alloc(int starting_count, int current_count)
{
    struct max_forwards *mf;
 
    mf = ast_malloc(sizeof(*mf));
    if (!mf) {
        return NULL;
    }
 
    mf->starting_count = starting_count;
    mf->current_count = current_count;
 
    return mf;
}
 
static void *max_forwards_duplicate(void *data)
{
    struct max_forwards *mf = data;
 
    return max_forwards_alloc(mf->starting_count, mf->current_count);
}
 
static void max_forwards_destroy(void *data)
{
    ast_free(data);
}
 
const struct ast_datastore_info max_forwards_info = {
    .type = "mfaled-interface",
    .duplicate = max_forwards_duplicate,
    .destroy = max_forwards_destroy,
};
 
static struct ast_datastore *max_forwards_datastore_alloc(struct ast_channel *chan,
        int starting_count)
{
    struct ast_datastore *mf_datastore;
    struct max_forwards *mf;
 
    mf_datastore = ast_datastore_alloc(&max_forwards_info, NULL);
    if (!mf_datastore) {
        return NULL;
    }
    mf_datastore->inheritance = DATASTORE_INHERIT_FOREVER;
 
    mf = max_forwards_alloc(starting_count, starting_count);
    if (!mf) {
        ast_datastore_free(mf_datastore);
        return NULL;
    }
    mf_datastore->data = mf;
 
    ast_channel_datastore_add(chan, mf_datastore);
 
    return mf_datastore;
}
 
static struct ast_datastore *max_forwards_datastore_find_or_alloc(struct ast_channel *chan)
{
    struct ast_datastore *mf_datastore;
 
    mf_datastore = ast_channel_datastore_find(chan, &max_forwards_info, NULL);
    if (!mf_datastore) {
        mf_datastore = max_forwards_datastore_alloc(chan, DEFAULT_MAX_FORWARDS);
    }
 
    return mf_datastore;
}
 
int ast_max_forwards_set(struct ast_channel *chan, int starting_count)
{
    struct ast_datastore *mf_datastore;
    struct max_forwards *mf;
 
    mf_datastore = max_forwards_datastore_find_or_alloc(chan);
    if (!mf_datastore) {
        return -1;
    }
 
    mf = mf_datastore->data;
    mf->starting_count = mf->current_count = starting_count;
 
    return 0;
}
 
int ast_max_forwards_get(struct ast_channel *chan)
{
    struct ast_datastore *mf_datastore;
    struct max_forwards *mf;
 
    mf_datastore = max_forwards_datastore_find_or_alloc(chan);
    if (!mf_datastore) {
        return -1;
    }
 
    mf = mf_datastore->data;
    return mf->current_count;
}
 
int ast_max_forwards_decrement(struct ast_channel *chan)
{
    struct ast_datastore *mf_datastore;
    struct max_forwards *mf;
 
    mf_datastore = max_forwards_datastore_find_or_alloc(chan);
    if (!mf_datastore) {
        return -1;
    }
 
    mf = mf_datastore->data;
    --mf->current_count;
 
    return 0;
}
 
int ast_max_forwards_reset(struct ast_channel *chan)
{
    struct ast_datastore *mf_datastore;
    struct max_forwards *mf;
 
    mf_datastore = max_forwards_datastore_find_or_alloc(chan);
    if (!mf_datastore) {
        return -1;
    }
 
    mf = mf_datastore->data;
    mf->current_count = mf->starting_count;
 
    return 0;
}