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Last updated: Sat Feb 3 05:00:33 2007

Asterisk developer's documentation :: Codename Pineapple

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chan_features.c

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/*
 * Asterisk -- An open source telephony toolkit.
 *
 * Copyright (C) 1999 - 2005, Digium, Inc.
 *
 * Mark Spencer <markster@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.
 */

/*! \file
 *
 * \brief feature Proxy Channel
 *
 * \author Mark Spencer <markster@digium.com>
 *
 * \note *** Experimental code ****
 * 
 * \ingroup channel_drivers
 */

#include "asterisk.h"

ASTERISK_FILE_VERSION(__FILE__, "$Revision: 51806 $")

#include <stdio.h>
#include <string.h>
#include <unistd.h>
#include <sys/socket.h>
#include <errno.h>
#include <stdlib.h>
#include <fcntl.h>
#include <netdb.h>
#include <netinet/in.h>
#include <arpa/inet.h>
#include <sys/signal.h>

#include "asterisk/lock.h"
#include "asterisk/channel.h"
#include "asterisk/config.h"
#include "asterisk/logger.h"
#include "asterisk/module.h"
#include "asterisk/pbx.h"
#include "asterisk/options.h"
#include "asterisk/lock.h"
#include "asterisk/sched.h"
#include "asterisk/io.h"
#include "asterisk/rtp.h"
#include "asterisk/acl.h"
#include "asterisk/callerid.h"
#include "asterisk/file.h"
#include "asterisk/cli.h"
#include "asterisk/app.h"
#include "asterisk/musiconhold.h"
#include "asterisk/manager.h"
#include "asterisk/stringfields.h"

static const char tdesc[] = "Feature Proxy Channel Driver";

#define IS_OUTBOUND(a,b) (a == b->chan ? 1 : 0)

struct feature_sub {
   struct ast_channel *owner;
   int inthreeway;
   int pfd;
   int timingfdbackup;
   int alertpipebackup[2];
};

struct feature_pvt {
   ast_mutex_t lock;       /* Channel private lock */
   char tech[AST_MAX_EXTENSION];    /* Technology to abstract */
   char dest[AST_MAX_EXTENSION];    /* Destination to abstract */
   struct ast_channel *subchan;
   struct feature_sub subs[3];      /* Subs */
   struct ast_channel *owner;    /* Current Master Channel */
   AST_LIST_ENTRY(feature_pvt) list;   /* Next entity */
};

static AST_LIST_HEAD_STATIC(features, feature_pvt);

#define SUB_REAL  0        /* Active call */
#define SUB_CALLWAIT 1        /* Call-Waiting call on hold */
#define SUB_THREEWAY 2        /* Three-way call */

static struct ast_channel *features_request(const char *type, int format, void *data, int *cause);
static int features_digit_begin(struct ast_channel *ast, char digit);
static int features_digit_end(struct ast_channel *ast, char digit, unsigned int duration);
static int features_call(struct ast_channel *ast, char *dest, int timeout);
static int features_hangup(struct ast_channel *ast);
static int features_answer(struct ast_channel *ast);
static struct ast_frame *features_read(struct ast_channel *ast);
static int features_write(struct ast_channel *ast, struct ast_frame *f);
static int features_indicate(struct ast_channel *ast, int condition, const void *data, size_t datalen);
static int features_fixup(struct ast_channel *oldchan, struct ast_channel *newchan);

static const struct ast_channel_tech features_tech = {
   .type = "Feature",
   .description = tdesc,
   .capabilities = -1,
   .requester = features_request,
   .send_digit_begin = features_digit_begin,
   .send_digit_end = features_digit_end,
   .call = features_call,
   .hangup = features_hangup,
   .answer = features_answer,
   .read = features_read,
   .write = features_write,
   .exception = features_read,
   .indicate = features_indicate,
   .fixup = features_fixup,
};

static inline void init_sub(struct feature_sub *sub)
{
   sub->inthreeway = 0;
   sub->pfd = -1;
   sub->timingfdbackup = -1;
   sub->alertpipebackup[0] = sub->alertpipebackup[1] = -1;
}

static inline int indexof(struct feature_pvt *p, struct ast_channel *owner, int nullok)
{
   int x;
   if (!owner) {
      ast_log(LOG_WARNING, "indexof called on NULL owner??\n");
      return -1;
   }
   for (x=0; x<3; x++) {
      if (owner == p->subs[x].owner)
         return x;
   }
   return -1;
}

#if 0
static void wakeup_sub(struct feature_pvt *p, int a)
{
   struct ast_frame null = { AST_FRAME_NULL, };
   for (;;) {
      if (p->subs[a].owner) {
         if (ast_mutex_trylock(&p->subs[a].owner->lock)) {
            ast_mutex_unlock(&p->lock);
            usleep(1);
            ast_mutex_lock(&p->lock);
         } else {
            ast_queue_frame(p->subs[a].owner, &null);
            ast_mutex_unlock(&p->subs[a].owner->lock);
            break;
         }
      } else
         break;
   }
}
#endif

static void restore_channel(struct feature_pvt *p, int index)
{
   /* Restore timing/alertpipe */
   p->subs[index].owner->timingfd = p->subs[index].timingfdbackup;
   p->subs[index].owner->alertpipe[0] = p->subs[index].alertpipebackup[0];
   p->subs[index].owner->alertpipe[1] = p->subs[index].alertpipebackup[1];
   p->subs[index].owner->fds[AST_ALERT_FD] = p->subs[index].alertpipebackup[0];
   p->subs[index].owner->fds[AST_TIMING_FD] = p->subs[index].timingfdbackup;
}

static void update_features(struct feature_pvt *p, int index)
{
   int x;
   if (p->subs[index].owner) {
      for (x=0; x<AST_MAX_FDS; x++) {
         if (index) 
            p->subs[index].owner->fds[x] = -1;
         else
            p->subs[index].owner->fds[x] = p->subchan->fds[x];
      }
      if (!index) {
         /* Copy timings from master channel */
         p->subs[index].owner->timingfd = p->subchan->timingfd;
         p->subs[index].owner->alertpipe[0] = p->subchan->alertpipe[0];
         p->subs[index].owner->alertpipe[1] = p->subchan->alertpipe[1];
         if (p->subs[index].owner->nativeformats != p->subchan->readformat) {
            p->subs[index].owner->nativeformats = p->subchan->readformat;
            if (p->subs[index].owner->readformat)
               ast_set_read_format(p->subs[index].owner, p->subs[index].owner->readformat);
            if (p->subs[index].owner->writeformat)
               ast_set_write_format(p->subs[index].owner, p->subs[index].owner->writeformat);
         }
      } else{
         restore_channel(p, index);
      }
   }
}

#if 0
static void swap_subs(struct feature_pvt *p, int a, int b)
{
   int tinthreeway;
   struct ast_channel *towner;

   if (option_debug)
      ast_log(LOG_DEBUG, "Swapping %d and %d\n", a, b);

   towner = p->subs[a].owner;
   tinthreeway = p->subs[a].inthreeway;

   p->subs[a].owner = p->subs[b].owner;
   p->subs[a].inthreeway = p->subs[b].inthreeway;

   p->subs[b].owner = towner;
   p->subs[b].inthreeway = tinthreeway;
   update_features(p,a);
   update_features(p,b);
   wakeup_sub(p, a);
   wakeup_sub(p, b);
}
#endif

static int features_answer(struct ast_channel *ast)
{
   struct feature_pvt *p = ast->tech_pvt;
   int res = -1;
   int x;

   ast_mutex_lock(&p->lock);
   x = indexof(p, ast, 0);
   if (!x && p->subchan)
      res = ast_answer(p->subchan);
   ast_mutex_unlock(&p->lock);
   return res;
}

static struct ast_frame  *features_read(struct ast_channel *ast)
{
   struct feature_pvt *p = ast->tech_pvt;
   struct ast_frame *f;
   int x;
   
   f = &ast_null_frame;
   ast_mutex_lock(&p->lock);
   x = indexof(p, ast, 0);
   if (!x && p->subchan) {
      update_features(p, x);
      f = ast_read(p->subchan);
   }
   ast_mutex_unlock(&p->lock);
   return f;
}

static int features_write(struct ast_channel *ast, struct ast_frame *f)
{
   struct feature_pvt *p = ast->tech_pvt;
   int res = -1;
   int x;

   ast_mutex_lock(&p->lock);
   x = indexof(p, ast, 0);
   if (!x && p->subchan)
      res = ast_write(p->subchan, f);
   ast_mutex_unlock(&p->lock);
   return res;
}

static int features_fixup(struct ast_channel *oldchan, struct ast_channel *newchan)
{
   struct feature_pvt *p = newchan->tech_pvt;
   int x;

   ast_mutex_lock(&p->lock);
   if (p->owner == oldchan)
      p->owner = newchan;
   for (x = 0; x < 3; x++) {
      if (p->subs[x].owner == oldchan)
         p->subs[x].owner = newchan;
   }
   ast_mutex_unlock(&p->lock);
   return 0;
}

static int features_indicate(struct ast_channel *ast, int condition, const void *data, size_t datalen)
{
   struct feature_pvt *p = ast->tech_pvt;
   int res = -1;
   int x;

   /* Queue up a frame representing the indication as a control frame */
   ast_mutex_lock(&p->lock);
   x = indexof(p, ast, 0);
   if (!x && p->subchan)
      res = ast_indicate(p->subchan, condition);
   ast_mutex_unlock(&p->lock);
   return res;
}

static int features_digit_begin(struct ast_channel *ast, char digit)
{
   struct feature_pvt *p = ast->tech_pvt;
   int res = -1;
   int x;

   /* Queue up a frame representing the indication as a control frame */
   ast_mutex_lock(&p->lock);
   x = indexof(p, ast, 0);
   if (!x && p->subchan)
      res = ast_senddigit_begin(p->subchan, digit);
   ast_mutex_unlock(&p->lock);

   return res;
}

static int features_digit_end(struct ast_channel *ast, char digit, unsigned int duration)
{
   struct feature_pvt *p = ast->tech_pvt;
   int res = -1;
   int x;

   /* Queue up a frame representing the indication as a control frame */
   ast_mutex_lock(&p->lock);
   x = indexof(p, ast, 0);
   if (!x && p->subchan)
      res = ast_senddigit_end(p->subchan, digit, duration);
   ast_mutex_unlock(&p->lock);
   return res;
}

static int features_call(struct ast_channel *ast, char *dest, int timeout)
{
   struct feature_pvt *p = ast->tech_pvt;
   int res = -1;
   int x;
   char *dest2;
      
   dest2 = strchr(dest, '/');
   if (dest2) {
      ast_mutex_lock(&p->lock);
      x = indexof(p, ast, 0);
      if (!x && p->subchan) {
         p->subchan->cid.cid_num = ast_strdup(p->owner->cid.cid_num);
         p->subchan->cid.cid_name = ast_strdup(p->owner->cid.cid_name);
         p->subchan->cid.cid_rdnis = ast_strdup(p->owner->cid.cid_rdnis);
         p->subchan->cid.cid_ani = ast_strdup(p->owner->cid.cid_ani);
      
         p->subchan->cid.cid_pres = p->owner->cid.cid_pres;
         ast_string_field_set(p->subchan, language, p->owner->language);
         ast_string_field_set(p->subchan, accountcode, p->owner->accountcode);
         p->subchan->cdrflags = p->owner->cdrflags;
         res = ast_call(p->subchan, dest2, timeout);
         update_features(p, x);
      } else
         ast_log(LOG_NOTICE, "Uhm yah, not quite there with the call waiting...\n");
      ast_mutex_unlock(&p->lock);
   }
   return res;
}

static int features_hangup(struct ast_channel *ast)
{
   struct feature_pvt *p = ast->tech_pvt;
   int x;

   ast_mutex_lock(&p->lock);
   x = indexof(p, ast, 0);
   if (x > -1) {
      restore_channel(p, x);
      p->subs[x].owner = NULL;
      /* XXX Re-arrange, unconference, etc XXX */
   }
   ast->tech_pvt = NULL;
   
   if (!p->subs[SUB_REAL].owner && !p->subs[SUB_CALLWAIT].owner && !p->subs[SUB_THREEWAY].owner) {
      ast_mutex_unlock(&p->lock);
      /* Remove from list */
      AST_LIST_LOCK(&features);
      AST_LIST_REMOVE(&features, p, list);
      AST_LIST_UNLOCK(&features);
      ast_mutex_lock(&p->lock);
      /* And destroy */
      if (p->subchan)
         ast_hangup(p->subchan);
      ast_mutex_unlock(&p->lock);
      ast_mutex_destroy(&p->lock);
      free(p);
      return 0;
   }
   ast_mutex_unlock(&p->lock);
   return 0;
}

static struct feature_pvt *features_alloc(char *data, int format)
{
   struct feature_pvt *tmp;
   char *dest=NULL;
   char *tech;
   int x;
   int status;
   struct ast_channel *chan;
   
   tech = ast_strdupa(data);
   if (tech) {
      dest = strchr(tech, '/');
      if (dest) {
         *dest = '\0';
         dest++;
      }
   }
   if (!tech || !dest) {
      ast_log(LOG_NOTICE, "Format for feature channel is Feature/Tech/Dest ('%s' not valid)!\n", 
         data);
      return NULL;
   }
   AST_LIST_LOCK(&features);
   AST_LIST_TRAVERSE(&features, tmp, list) {
      if (!strcasecmp(tmp->tech, tech) && !strcmp(tmp->dest, dest))
         break;
   }
   AST_LIST_UNLOCK(&features);
   if (!tmp) {
      chan = ast_request(tech, format, dest, &status);
      if (!chan) {
         ast_log(LOG_NOTICE, "Unable to allocate subchannel '%s/%s'\n", tech, dest);
         return NULL;
      }
      tmp = malloc(sizeof(struct feature_pvt));
      if (tmp) {
         memset(tmp, 0, sizeof(struct feature_pvt));
         for (x=0;x<3;x++)
            init_sub(tmp->subs + x);
         ast_mutex_init(&tmp->lock);
         ast_copy_string(tmp->tech, tech, sizeof(tmp->tech));
         ast_copy_string(tmp->dest, dest, sizeof(tmp->dest));
         tmp->subchan = chan;
         AST_LIST_LOCK(&features);
         AST_LIST_INSERT_HEAD(&features, tmp, list);
         AST_LIST_UNLOCK(&features);
      }
   }
   return tmp;
}

static struct ast_channel *features_new(struct feature_pvt *p, int state, int index)
{
   struct ast_channel *tmp;
   int x,y;
   char *b2 = 0;
   if (!p->subchan) {
      ast_log(LOG_WARNING, "Called upon channel with no subchan:(\n");
      return NULL;
   }
   if (p->subs[index].owner) {
      ast_log(LOG_WARNING, "Called to put index %d already there!\n", index);
      return NULL;
   }
   /* figure out what you want the name to be */
   for (x=1;x<4;x++) {
      if (b2)
         free(b2);
      asprintf(&b2, "Feature/%s/%s-%d", p->tech, p->dest, x);
      for (y=0;y<3;y++) {
         if (y == index)
            continue;
         if (p->subs[y].owner && !strcasecmp(p->subs[y].owner->name, b2))
            break;
      }
      if (y >= 3)
         break;
   }
   tmp = ast_channel_alloc(0, state, 0,0, b2);
   /* free up the name, it was copied into the channel name */
   if (b2)
      free(b2);
   if (!tmp) {
      ast_log(LOG_WARNING, "Unable to allocate channel structure\n");
      return NULL;
   }
   tmp->tech = &features_tech;
   tmp->writeformat = p->subchan->writeformat;
   tmp->rawwriteformat = p->subchan->rawwriteformat;
   tmp->readformat = p->subchan->readformat;
   tmp->rawreadformat = p->subchan->rawreadformat;
   tmp->nativeformats = p->subchan->readformat;
   tmp->tech_pvt = p;
   p->subs[index].owner = tmp;
   if (!p->owner)
      p->owner = tmp;
   ast_module_ref(ast_module_info->self);
   return tmp;
}


static struct ast_channel *features_request(const char *type, int format, void *data, int *cause)
{
   struct feature_pvt *p;
   struct ast_channel *chan = NULL;

   p = features_alloc(data, format);
   if (p && !p->subs[SUB_REAL].owner)
      chan = features_new(p, AST_STATE_DOWN, SUB_REAL);
   if (chan)
      update_features(p,SUB_REAL);
   return chan;
}

static int features_show(int fd, int argc, char **argv)
{
   struct feature_pvt *p;

   if (argc != 3)
      return RESULT_SHOWUSAGE;

   if (AST_LIST_EMPTY(&features)) {
      ast_cli(fd, "No feature channels in use\n");
      return RESULT_SUCCESS;
   }

   AST_LIST_LOCK(&features);
   AST_LIST_TRAVERSE(&features, p, list) {
      ast_mutex_lock(&p->lock);
      ast_cli(fd, "%s -- %s/%s\n", p->owner ? p->owner->name : "<unowned>", p->tech, p->dest);
      ast_mutex_unlock(&p->lock);
   }
   AST_LIST_UNLOCK(&features);
   return RESULT_SUCCESS;
}

static const char show_features_usage[] = 
"Usage: feature show channels\n"
"       Provides summary information on feature channels.\n";

static struct ast_cli_entry cli_features[] = {
   { { "feature", "show", "channels", NULL },
   features_show, "List status of feature channels",
   show_features_usage },
};

static int load_module(void)
{
   /* Make sure we can register our sip channel type */
   if (ast_channel_register(&features_tech)) {
      ast_log(LOG_ERROR, "Unable to register channel class 'Feature'\n");
      return -1;
   }
   ast_cli_register_multiple(cli_features, sizeof(cli_features) / sizeof(struct ast_cli_entry));
   return 0;
}

static int unload_module(void)
{
   struct feature_pvt *p;
   
   /* First, take us out of the channel loop */
   ast_cli_unregister_multiple(cli_features, sizeof(cli_features) / sizeof(struct ast_cli_entry));
   ast_channel_unregister(&features_tech);
   
   if (!AST_LIST_LOCK(&features))
      return -1;
   /* Hangup all interfaces if they have an owner */
   AST_LIST_TRAVERSE_SAFE_BEGIN(&features, p, list) {
      if (p->owner)
         ast_softhangup(p->owner, AST_SOFTHANGUP_APPUNLOAD);
      AST_LIST_REMOVE_CURRENT(&features, list);
      free(p);
   }
   AST_LIST_TRAVERSE_SAFE_END
   AST_LIST_UNLOCK(&features);
   
   return 0;
}

AST_MODULE_INFO_STANDARD(ASTERISK_GPL_KEY, "Feature Proxy Channel");

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