func_scramble.c File Reference

Frequency inverter. More...

#include "asterisk.h"
#include "asterisk/module.h"
#include "asterisk/channel.h"
#include "asterisk/pbx.h"
#include "asterisk/utils.h"
#include "asterisk/audiohook.h"
#include "asterisk/app.h"
#include <stdio.h>
#include <string.h>

Include dependency graph for func_scramble.c:

Go to the source code of this file.

Data Structures
struct	scramble_information

Functions
static void	__reg_module (void)
static void	__unreg_module (void)
struct ast_module *	AST_MODULE_SELF_SYM (void)
static void	destroy_callback (void *data)
static void	freq_invert (short *amp, int samples)
static int	load_module (void)
static int	remove_scrambler (struct ast_channel *chan)
static int	scramble_callback (struct ast_audiohook *audiohook, struct ast_channel *chan, struct ast_frame *frame, enum ast_audiohook_direction direction)
static int	scramble_write (struct ast_channel *chan, const char *cmd, char *data, const char *value)
static int	unload_module (void)

Variables
static struct ast_module_info	__mod_info = { .name = AST_MODULE, .flags = AST_MODFLAG_LOAD_ORDER , .description = "Frequency inverting voice scrambler" , .key = "This paragraph is copyright (c) 2006 by Digium, Inc. \In order for your module to load, it must return this \key via a function called \"key\". Any code which \includes this paragraph must be licensed under the GNU \General Public License version 2 or later (at your \option). In addition to Digium's general reservations \of rights, Digium expressly reserves the right to \allow other parties to license this paragraph under \different terms. Any use of Digium, Inc. trademarks or \logos (including \"Asterisk\" or \"Digium\") without \express written permission of Digium, Inc. is prohibited.\n" , .buildopt_sum = AST_BUILDOPT_SUM, .load = load_module, .unload = unload_module, .load_pri = AST_MODPRI_DEFAULT, .support_level = AST_MODULE_SUPPORT_CORE, }
static const struct ast_module_info *	ast_module_info = &__mod_info
static const struct ast_datastore_info	scramble_datastore
	Static structure for datastore information. More...
static struct ast_custom_function	scramble_function

Detailed Description

Frequency inverter.

Author

Naveen Albert aster.nosp@m.isk@.nosp@m.phrea.nosp@m.knet.nosp@m..org

Definition in file func_scramble.c.

Function Documentation

__reg_module()

static void __reg_module ( void  )

static

Definition at line 241 of file func_scramble.c.

__unreg_module()

static void __unreg_module ( void  )

static

Definition at line 241 of file func_scramble.c.

AST_MODULE_SELF_SYM()

struct ast_module * AST_MODULE_SELF_SYM

(

void

)

Definition at line 241 of file func_scramble.c.

destroy_callback()

static void destroy_callback ( void *  data )

static

Definition at line 82 of file func_scramble.c.

{
    struct scramble_information *ni = data;
 
    /* Destroy the audiohook, and destroy ourselves */
    ast_audiohook_lock(&ni->audiohook);
    ast_audiohook_detach(&ni->audiohook);
    ast_audiohook_unlock(&ni->audiohook);
    ast_audiohook_destroy(&ni->audiohook);
    ast_free(ni);
 
    return;
}

References ast_audiohook_destroy(), ast_audiohook_detach(), ast_audiohook_lock, ast_audiohook_unlock, ast_free, and scramble_information::audiohook.

freq_invert()

static void freq_invert ( short *  amp, int  samples  )

inlinestatic

Definition at line 103 of file func_scramble.c.

{
    int i;
    /* invert every other sample by 1 */
    for (i = 0; i < samples; i += 2) {
        amp[i] = -amp[i];
    }
}

Referenced by scramble_callback().

load_module()

static int load_module ( void  )

static

Definition at line 236 of file func_scramble.c.

{
    return ast_custom_function_register(&scramble_function);
}

References ast_custom_function_register, and scramble_function.

remove_scrambler()

static int remove_scrambler ( struct ast_channel *  chan )

static

Definition at line 140 of file func_scramble.c.

{
    struct ast_datastore *datastore = NULL;
    struct scramble_information *data;
    SCOPED_CHANNELLOCK(chan_lock, chan);
 
    datastore = ast_channel_datastore_find(chan, &scramble_datastore, NULL);
    if (!datastore) {
        ast_log(AST_LOG_WARNING, "Cannot remove SCRAMBLE from %s: SCRAMBLE not currently enabled\n",
                ast_channel_name(chan));
        return -1;
    }
    data = datastore->data;
 
    if (ast_audiohook_remove(chan, &data->audiohook)) {
        ast_log(AST_LOG_WARNING, "Failed to remove SCRAMBLE audiohook from channel %s\n", ast_channel_name(chan));
        return -1;
    }
 
    if (ast_channel_datastore_remove(chan, datastore)) {
        ast_log(AST_LOG_WARNING, "Failed to remove SCRAMBLE datastore from channel %s\n",
                ast_channel_name(chan));
        return -1;
    }
    ast_datastore_free(datastore);
 
    return 0;
}

References ast_audiohook_remove(), ast_channel_datastore_find(), ast_channel_datastore_remove(), ast_channel_name(), ast_datastore_free(), ast_log, AST_LOG_WARNING, scramble_information::audiohook, ast_datastore::data, NULL, SCOPED_CHANNELLOCK, and scramble_datastore.

Referenced by scramble_write().

scramble_callback()

static int scramble_callback ( struct ast_audiohook *  audiohook, struct ast_channel *  chan, struct ast_frame *  frame, enum ast_audiohook_direction  direction  )

static

Definition at line 112 of file func_scramble.c.

{
    struct ast_datastore *datastore = NULL;
    struct scramble_information *ni = NULL;
 
    /* If the audiohook is stopping it means the channel is shutting down.... but we let the datastore destroy take care of it */
    if (audiohook->status == AST_AUDIOHOOK_STATUS_DONE) {
        return 0;
    }
 
    /* Grab datastore which contains our gain information */
    if (!(datastore = ast_channel_datastore_find(chan, &scramble_datastore, NULL))) {
        return 0;
    }
 
    if (frame->frametype == AST_FRAME_VOICE) { /* only invert voice frequencies */
        ni = datastore->data;
        /* Based on direction of frame, and confirm it is applicable */
        if (!(direction == AST_AUDIOHOOK_DIRECTION_READ ? ni->rx : ni->tx)) {
            return 0;
        }
        /* Scramble the sample now */
        freq_invert(frame->data.ptr, frame->samples);
    }
    return 0;
}

References AST_AUDIOHOOK_DIRECTION_READ, AST_AUDIOHOOK_STATUS_DONE, ast_channel_datastore_find(), AST_FRAME_VOICE, scramble_information::audiohook, ast_datastore::data, ast_frame::data, ast_frame::frametype, freq_invert(), NULL, ast_frame::ptr, scramble_information::rx, ast_frame::samples, scramble_datastore, ast_audiohook::status, and scramble_information::tx.

Referenced by scramble_write().

scramble_write()

static int scramble_write ( struct ast_channel *  chan, const char *  cmd, char *  data, const char *  value  )

static

Definition at line 169 of file func_scramble.c.

{
    char *parse;
    struct ast_datastore *datastore = NULL;
    struct scramble_information *ni = NULL;
    int tx = 1, rx = 1;
 
    AST_DECLARE_APP_ARGS(args,
        AST_APP_ARG(direction);
    );
 
    if (!chan) {
        ast_log(LOG_WARNING, "No channel was provided to %s function.\n", cmd);
        return -1;
    }
 
    parse = ast_strdupa(value);
    AST_STANDARD_APP_ARGS(args, parse);
 
    if (!strcasecmp(args.direction, "remove")) {
        return remove_scrambler(chan);
    }
    if (!strcasecmp(args.direction, "tx")) {
        tx = 1;
        rx = 0;
    } else if (!strcasecmp(args.direction, "rx")) {
        rx = 0;
        tx = 1;
    } else if (strcasecmp(args.direction, "both")) {
        ast_log(LOG_ERROR, "Direction must be either RX, TX, both, or remove\n");
        return -1;
    }
    ast_channel_lock(chan);
    if (!(datastore = ast_channel_datastore_find(chan, &scramble_datastore, NULL))) {
        /* Allocate a new datastore to hold the reference to this audiohook information */
        if (!(datastore = ast_datastore_alloc(&scramble_datastore, NULL))) {
            return 0;
        }
        if (!(ni = ast_calloc(1, sizeof(*ni)))) {
            ast_datastore_free(datastore);
            return 0;
        }
        ast_audiohook_init(&ni->audiohook, AST_AUDIOHOOK_TYPE_MANIPULATE, "Voice scrambler", AST_AUDIOHOOK_MANIPULATE_ALL_RATES);
        ni->audiohook.manipulate_callback = scramble_callback;
        datastore->data = ni;
        ast_channel_datastore_add(chan, datastore);
        ast_audiohook_attach(chan, &ni->audiohook);
    } else {
        ni = datastore->data;
    }
    ni->tx = tx;
    ni->rx = rx;
    ast_channel_unlock(chan);
 
    return 0;
}

References args, AST_APP_ARG, ast_audiohook_attach(), ast_audiohook_init(), AST_AUDIOHOOK_MANIPULATE_ALL_RATES, AST_AUDIOHOOK_TYPE_MANIPULATE, ast_calloc, ast_channel_datastore_add(), ast_channel_datastore_find(), ast_channel_lock, ast_channel_unlock, ast_datastore_alloc, ast_datastore_free(), AST_DECLARE_APP_ARGS, ast_log, AST_STANDARD_APP_ARGS, ast_strdupa, scramble_information::audiohook, ast_datastore::data, LOG_ERROR, LOG_WARNING, ast_audiohook::manipulate_callback, NULL, remove_scrambler(), scramble_information::rx, scramble_callback(), scramble_datastore, scramble_information::tx, and value.

unload_module()

static int unload_module ( void  )

static

Definition at line 231 of file func_scramble.c.

{
    return ast_custom_function_unregister(&scramble_function);
}

References ast_custom_function_unregister(), and scramble_function.

Variable Documentation

__mod_info

struct ast_module_info __mod_info = { .name = AST_MODULE, .flags = AST_MODFLAG_LOAD_ORDER , .description = "Frequency inverting voice scrambler" , .key = "This paragraph is copyright (c) 2006 by Digium, Inc. \In order for your module to load, it must return this \key via a function called \"key\". Any code which \includes this paragraph must be licensed under the GNU \General Public License version 2 or later (at your \option). In addition to Digium's general reservations \of rights, Digium expressly reserves the right to \allow other parties to license this paragraph under \different terms. Any use of Digium, Inc. trademarks or \logos (including \"Asterisk\" or \"Digium\") without \express written permission of Digium, Inc. is prohibited.\n" , .buildopt_sum = AST_BUILDOPT_SUM, .load = load_module, .unload = unload_module, .load_pri = AST_MODPRI_DEFAULT, .support_level = AST_MODULE_SUPPORT_CORE, }

static

Definition at line 241 of file func_scramble.c.

ast_module_info

const struct ast_module_info* ast_module_info = &__mod_info

static

Definition at line 241 of file func_scramble.c.

scramble_datastore

const struct ast_datastore_info scramble_datastore

static

Initial value:

= {
    .type = "scramble",
    .destroy = destroy_callback
}

Static structure for datastore information.

Definition at line 97 of file func_scramble.c.

Referenced by remove_scrambler(), scramble_callback(), and scramble_write().

scramble_function

struct ast_custom_function scramble_function

static

Initial value:

= {
    .name = "SCRAMBLE",
    .write = scramble_write,
}

Definition at line 226 of file func_scramble.c.

Referenced by load_module(), and unload_module().