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 = ASTERISK_GPL_KEY , .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.
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 243 of file func_scramble.c.

__unreg_module()

static void __unreg_module ( void  )

static

Definition at line 243 of file func_scramble.c.

AST_MODULE_SELF_SYM()

struct ast_module * AST_MODULE_SELF_SYM

(

void

)

Definition at line 243 of file func_scramble.c.

destroy_callback()

static void destroy_callback ( void *  data )

static

Definition at line 84 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 105 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 238 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 142 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 114 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 171 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 233 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 = ASTERISK_GPL_KEY , .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 243 of file func_scramble.c.

ast_module_info

const struct ast_module_info* ast_module_info = &__mod_info

static

Definition at line 243 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 99 of file func_scramble.c.

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

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 228 of file func_scramble.c.

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

Referenced by load_module(), and unload_module().