channel.c

					ast_cdr_answer(chan->cdr);
				}
			}
			break;
		case AST_FRAME_DTMF:
			ast_log(LOG_DTMF, "DTMF '%c' received on %s\n", f->subclass, chan->name);
			if (ast_test_flag(chan, AST_FLAG_DEFER_DTMF)) {
				if (strlen(chan->dtmfq) < sizeof(chan->dtmfq) - 2)
					chan->dtmfq[strlen(chan->dtmfq)] = f->subclass;
				else
					ast_log(LOG_WARNING, "Dropping deferred DTMF digits on %s\n", chan->name);
				ast_frfree(f);
				f = &ast_null_frame;
			}
			break;
		case AST_FRAME_DTMF_BEGIN:
			ast_log(LOG_DTMF, "DTMF begin '%c' received on %s\n", f->subclass, chan->name);
			break;
		case AST_FRAME_DTMF_END:
			ast_log(LOG_DTMF, "DTMF end '%c' received on %s\n", f->subclass, chan->name);
			break;
		case AST_FRAME_VOICE:
			if (dropaudio) {
				ast_frfree(f);
				f = &ast_null_frame;
			} else if (!(f->subclass & chan->nativeformats)) {
				/* This frame can't be from the current native formats -- drop it on the
				   floor */
				ast_log(LOG_NOTICE, "Dropping incompatible voice frame on %s of format %s since our native format has changed to %s\n",
					chan->name, ast_getformatname(f->subclass), ast_getformatname(chan->nativeformats));
				ast_frfree(f);
				f = &ast_null_frame;
			} else {
				if (chan->spies)
					queue_frame_to_spies(chan, f, SPY_READ);
				
				if (chan->monitor && chan->monitor->read_stream ) {
					/* XXX what does this do ? */
#ifndef MONITOR_CONSTANT_DELAY
					int jump = chan->outsmpl - chan->insmpl - 4 * f->samples;
					if (jump >= 0) {
						if (ast_seekstream(chan->monitor->read_stream, jump + f->samples, SEEK_FORCECUR) == -1)
							ast_log(LOG_WARNING, "Failed to perform seek in monitoring read stream, synchronization between the files may be broken\n");
						chan->insmpl += jump + 4 * f->samples;
					} else
						chan->insmpl+= f->samples;
#else
					int jump = chan->outsmpl - chan->insmpl;
					if (jump - MONITOR_DELAY >= 0) {
						if (ast_seekstream(chan->monitor->read_stream, jump - f->samples, SEEK_FORCECUR) == -1)
							ast_log(LOG_WARNING, "Failed to perform seek in monitoring read stream, synchronization between the files may be broken\n");
						chan->insmpl += jump;
					} else
						chan->insmpl += f->samples;
#endif
					if (chan->monitor->state == AST_MONITOR_RUNNING) {
						if (ast_writestream(chan->monitor->read_stream, f) < 0)
							ast_log(LOG_WARNING, "Failed to write data to channel monitor read stream\n");
					}
				}

				if (chan->readtrans && (f = ast_translate(chan->readtrans, f, 1)) == NULL)
					f = &ast_null_frame;

				/* Run generator sitting on the line if timing device not available
				* and synchronous generation of outgoing frames is necessary       */
				if (chan->generatordata &&  !ast_internal_timing_enabled(chan)) {
					void *tmp = chan->generatordata;
					int res;

					if (chan->timingfunc) {
						if (option_debug > 1)
							ast_log(LOG_DEBUG, "Generator got voice, switching to phase locked mode\n");
						ast_settimeout(chan, 0, NULL, NULL);
					}

					chan->generatordata = NULL;	/* reset, to let writes go through */
					res = chan->generator->generate(chan, tmp, f->datalen, f->samples);
					chan->generatordata = tmp;
					if (res) {
						if (option_debug > 1)
							ast_log(LOG_DEBUG, "Auto-deactivating generator\n");
						ast_deactivate_generator(chan);
					}

				} else if (f->frametype == AST_FRAME_CNG) {
					if (chan->generator && !chan->timingfunc && (chan->timingfd > -1)) {
						if (option_debug > 1)
							ast_log(LOG_DEBUG, "Generator got CNG, switching to timed mode\n");
						ast_settimeout(chan, 160, generator_force, chan);
					}
				}
			}
		}
	} else {
		/* Make sure we always return NULL in the future */
		chan->_softhangup |= AST_SOFTHANGUP_DEV;
		if (chan->generator)
			ast_deactivate_generator(chan);
		/* End the CDR if appropriate */
		if (chan->cdr)
			ast_cdr_end(chan->cdr);
	}

	/* High bit prints debugging */
	if (chan->fin & DEBUGCHAN_FLAG)
		ast_frame_dump(chan->name, f, "<<");
	chan->fin = FRAMECOUNT_INC(chan->fin);

done:
	ast_channel_unlock(chan);
	return f;
}

int ast_internal_timing_enabled(struct ast_channel *chan)
{
	int ret = ast_opt_internal_timing && chan->timingfd > -1;
	if (option_debug > 4)
		ast_log(LOG_DEBUG, "Internal timing is %s (option_internal_timing=%d chan->timingfd=%d)\n", ret? "enabled": "disabled", ast_opt_internal_timing, chan->timingfd);
	return ret;
}

struct ast_frame *ast_read(struct ast_channel *chan)
{
	return __ast_read(chan, 0);
}

struct ast_frame *ast_read_noaudio(struct ast_channel *chan)
{
	return __ast_read(chan, 1);
}

int ast_indicate(struct ast_channel *chan, int condition)
{
	return ast_indicate_data(chan, condition, NULL, 0);
}

int ast_indicate_data(struct ast_channel *chan, int condition, const void *data, size_t datalen)
{
	int res = -1;

	ast_channel_lock(chan);
	/* Stop if we're a zombie or need a soft hangup */
	if (ast_test_flag(chan, AST_FLAG_ZOMBIE) || ast_check_hangup(chan)) {
		ast_channel_unlock(chan);
		return -1;
	}
	if (chan->tech->indicate)
		res = chan->tech->indicate(chan, condition, data, datalen);
	ast_channel_unlock(chan);
	if (!chan->tech->indicate || res) {
		/*
		 * Device does not support (that) indication, lets fake
		 * it by doing our own tone generation. (PM2002)
		 */
		if (condition < 0)
			ast_playtones_stop(chan);
		else {
			const struct tone_zone_sound *ts = NULL;
			switch (condition) {
			case AST_CONTROL_RINGING:
				ts = ast_get_indication_tone(chan->zone, "ring");
				break;
			case AST_CONTROL_BUSY:
				ts = ast_get_indication_tone(chan->zone, "busy");
				break;
			case AST_CONTROL_CONGESTION:
				ts = ast_get_indication_tone(chan->zone, "congestion");
				break;
			}
			if (ts && ts->data[0]) {
				ast_log(LOG_DEBUG, "Driver for channel '%s' does not support indication %d, emulating it\n", chan->name, condition);
				ast_playtones_start(chan,0,ts->data, 1);
				res = 0;
			} else if (condition == AST_CONTROL_PROGRESS) {
				/* ast_playtones_stop(chan); */
			} else if (condition == AST_CONTROL_PROCEEDING) {
				/* Do nothing, really */
			} else if (condition == AST_CONTROL_HOLD) {
				/* Do nothing.... */
			} else if (condition == AST_CONTROL_UNHOLD) {
				/* Do nothing.... */
			} else if (condition == AST_CONTROL_VIDUPDATE) {
				/* Do nothing.... */
			} else {
				/* not handled */
				ast_log(LOG_WARNING, "Unable to handle indication %d for '%s'\n", condition, chan->name);
				res = -1;
			}
		}
	}
	return res;
}

int ast_recvchar(struct ast_channel *chan, int timeout)
{
	int c;
	char *buf = ast_recvtext(chan, timeout);
	if (buf == NULL)
		return -1;	/* error or timeout */
	c = *(unsigned char *)buf;
	free(buf);
	return c;
}

char *ast_recvtext(struct ast_channel *chan, int timeout)
{
	int res, done = 0;
	char *buf = NULL;
	
	while (!done) {
		struct ast_frame *f;
		if (ast_check_hangup(chan))
			break;
		res = ast_waitfor(chan, timeout);
		if (res <= 0) /* timeout or error */
			break;
		timeout = res;	/* update timeout */
		f = ast_read(chan);
		if (f == NULL)
			break; /* no frame */
		if (f->frametype == AST_FRAME_CONTROL && f->subclass == AST_CONTROL_HANGUP)
			done = 1;	/* force a break */
		else if (f->frametype == AST_FRAME_TEXT) {		/* what we want */
			buf = ast_strndup((char *) f->data, f->datalen);	/* dup and break */
			done = 1;
		}
		ast_frfree(f);
	}
	return buf;
}

int ast_sendtext(struct ast_channel *chan, const char *text)
{
	int res = 0;
	/* Stop if we're a zombie or need a soft hangup */
	if (ast_test_flag(chan, AST_FLAG_ZOMBIE) || ast_check_hangup(chan))
		return -1;
	CHECK_BLOCKING(chan);
	if (chan->tech->send_text)
		res = chan->tech->send_text(chan, text);
	ast_clear_flag(chan, AST_FLAG_BLOCKING);
	return res;
}

static int do_senddigit(struct ast_channel *chan, char digit)
{
	int res = -1;

	if (chan->tech->send_digit)
		res = chan->tech->send_digit(chan, digit);
	if (res) {
		/*
		 * Device does not support DTMF tones, lets fake
		 * it by doing our own generation. (PM2002)
		 */
		static const char* dtmf_tones[] = {
			"!941+1336/100,!0/100",	/* 0 */
			"!697+1209/100,!0/100",	/* 1 */
			"!697+1336/100,!0/100",	/* 2 */
			"!697+1477/100,!0/100",	/* 3 */
			"!770+1209/100,!0/100",	/* 4 */
			"!770+1336/100,!0/100",	/* 5 */
			"!770+1477/100,!0/100",	/* 6 */
			"!852+1209/100,!0/100",	/* 7 */
			"!852+1336/100,!0/100",	/* 8 */
			"!852+1477/100,!0/100",	/* 9 */
			"!697+1633/100,!0/100",	/* A */
			"!770+1633/100,!0/100",	/* B */
			"!852+1633/100,!0/100",	/* C */
			"!941+1633/100,!0/100",	/* D */
			"!941+1209/100,!0/100",	/* * */
			"!941+1477/100,!0/100" };	/* # */
		if (digit >= '0' && digit <='9')
			ast_playtones_start(chan, 0, dtmf_tones[digit-'0'], 0);
		else if (digit >= 'A' && digit <= 'D')
			ast_playtones_start(chan, 0, dtmf_tones[digit-'A'+10], 0);
		else if (digit == '*')
			ast_playtones_start(chan, 0, dtmf_tones[14], 0);
		else if (digit == '#')
			ast_playtones_start(chan, 0, dtmf_tones[15], 0);
		else {
			/* not handled */
			ast_log(LOG_DEBUG, "Unable to generate DTMF tone '%c' for '%s'\n", digit, chan->name);
		}
	}
	return 0;
}

int ast_senddigit(struct ast_channel *chan, char digit)
{
	return do_senddigit(chan, digit);
}

int ast_prod(struct ast_channel *chan)
{
	struct ast_frame a = { AST_FRAME_VOICE };
	char nothing[128];

	/* Send an empty audio frame to get things moving */
	if (chan->_state != AST_STATE_UP) {
		ast_log(LOG_DEBUG, "Prodding channel '%s'\n", chan->name);
		a.subclass = chan->rawwriteformat;
		a.data = nothing + AST_FRIENDLY_OFFSET;
		a.src = "ast_prod";
		if (ast_write(chan, &a))
			ast_log(LOG_WARNING, "Prodding channel '%s' failed\n", chan->name);
	}
	return 0;
}

int ast_write_video(struct ast_channel *chan, struct ast_frame *fr)
{
	int res;
	if (!chan->tech->write_video)
		return 0;
	res = ast_write(chan, fr);
	if (!res)
		res = 1;
	return res;
}

int ast_write(struct ast_channel *chan, struct ast_frame *fr)
{
	int res = -1;
	struct ast_frame *f = NULL;

	/* Stop if we're a zombie or need a soft hangup */
	ast_channel_lock(chan);
	if (ast_test_flag(chan, AST_FLAG_ZOMBIE) || ast_check_hangup(chan))
		goto done;

	/* Handle any pending masquerades */
	if (chan->masq && ast_do_masquerade(chan)) {
		ast_log(LOG_WARNING, "Failed to perform masquerade\n");
		goto done;
	}
	if (chan->masqr) {
		res = 0;	/* XXX explain, why 0 ? */
		goto done;
	}
	if (chan->generatordata) {
		if (ast_test_flag(chan, AST_FLAG_WRITE_INT))
			ast_deactivate_generator(chan);
		else {
			res = 0;	/* XXX explain, why 0 ? */
			goto done;
		}
	}
	/* High bit prints debugging */
	if (chan->fout & DEBUGCHAN_FLAG)
		ast_frame_dump(chan->name, fr, ">>");
	CHECK_BLOCKING(chan);
	switch(fr->frametype) {
	case AST_FRAME_CONTROL:
		/* XXX Interpret control frames XXX */
		ast_log(LOG_WARNING, "Don't know how to handle control frames yet\n");
		break;
	case AST_FRAME_DTMF_BEGIN:
		res = (chan->tech->send_digit_begin == NULL) ? 0 :
			chan->tech->send_digit_begin(chan, fr->subclass);
		break;
	case AST_FRAME_DTMF_END:
		res = (chan->tech->send_digit_end == NULL) ? 0 :
			chan->tech->send_digit_end(chan);
		break;
	case AST_FRAME_DTMF:
		ast_clear_flag(chan, AST_FLAG_BLOCKING);
		ast_channel_unlock(chan);
		res = do_senddigit(chan,fr->subclass);
		ast_channel_lock(chan);
		CHECK_BLOCKING(chan);
		break;
	case AST_FRAME_TEXT:
		res = (chan->tech->send_text == NULL) ? 0 :
			chan->tech->send_text(chan, (char *) fr->data);
		break;
	case AST_FRAME_HTML:
		res = (chan->tech->send_html == NULL) ? 0 :
			chan->tech->send_html(chan, fr->subclass, (char *) fr->data, fr->datalen);
		break;
	case AST_FRAME_VIDEO:
		/* XXX Handle translation of video codecs one day XXX */
		res = (chan->tech->write_video == NULL) ? 0 :
			chan->tech->write_video(chan, fr);
		break;
	case AST_FRAME_MODEM:
		res = (chan->tech->write == NULL) ? 0 :
			chan->tech->write(chan, fr);
		break;
	case AST_FRAME_VOICE:
		if (chan->tech->write == NULL)
			break;	/*! \todo XXX should return 0 maybe ? */

		/* Bypass translator if we're writing format in the raw write format.  This
		   allows mixing of native / non-native formats */
		if (fr->subclass == chan->rawwriteformat)
			f = fr;
		else
			f = (chan->writetrans) ? ast_translate(chan->writetrans, fr, 0) : fr;
		if (f == NULL) {
			res = 0;
		} else {
			if (chan->spies)
				queue_frame_to_spies(chan, f, SPY_WRITE);

			if (chan->monitor && chan->monitor->write_stream) {
				/* XXX must explain this code */
#ifndef MONITOR_CONSTANT_DELAY
				int jump = chan->insmpl - chan->outsmpl - 4 * f->samples;
				if (jump >= 0) {
					if (ast_seekstream(chan->monitor->write_stream, jump + f->samples, SEEK_FORCECUR) == -1)
						ast_log(LOG_WARNING, "Failed to perform seek in monitoring write stream, synchronization between the files may be broken\n");
					chan->outsmpl += jump + 4 * f->samples;
				} else
					chan->outsmpl += f->samples;
#else
				int jump = chan->insmpl - chan->outsmpl;
				if (jump - MONITOR_DELAY >= 0) {
					if (ast_seekstream(chan->monitor->write_stream, jump - f->samples, SEEK_FORCECUR) == -1)
						ast_log(LOG_WARNING, "Failed to perform seek in monitoring write stream, synchronization between the files may be broken\n");
					chan->outsmpl += jump;
				} else
					chan->outsmpl += f->samples;
#endif
				if (chan->monitor->state == AST_MONITOR_RUNNING) {
					if (ast_writestream(chan->monitor->write_stream, f) < 0)
						ast_log(LOG_WARNING, "Failed to write data to channel monitor write stream\n");
				}
			}

			res = chan->tech->write(chan, f);
		}
		break;	
	}

	if (f && f != fr)
		ast_frfree(f);
	ast_clear_flag(chan, AST_FLAG_BLOCKING);
	/* Consider a write failure to force a soft hangup */
	if (res < 0)
		chan->_softhangup |= AST_SOFTHANGUP_DEV;
	else {
		chan->fout = FRAMECOUNT_INC(chan->fout);
	}
done:
	ast_channel_unlock(chan);
	return res;
}

static int set_format(struct ast_channel *chan, int fmt, int *rawformat, int *format,
		      struct ast_trans_pvt **trans, const int direction)
{
	int native;
	int res;
	
	/* Make sure we only consider audio */
	fmt &= AST_FORMAT_AUDIO_MASK;
	
	native = chan->nativeformats;
	/* Find a translation path from the native format to one of the desired formats */
	if (!direction)
		/* reading */
		res = ast_translator_best_choice(&fmt, &native);
	else
		/* writing */
		res = ast_translator_best_choice(&native, &fmt);

	if (res < 0) {
		ast_log(LOG_WARNING, "Unable to find a codec translation path from %s to %s\n",
			ast_getformatname(native), ast_getformatname(fmt));
		return -1;
	}
	
	/* Now we have a good choice for both. */
	ast_channel_lock(chan);
	*rawformat = native;
	/* User perspective is fmt */
	*format = fmt;
	/* Free any read translation we have right now */
	if (*trans)
		ast_translator_free_path(*trans);
	/* Build a translation path from the raw format to the desired format */
	if (!direction)
		/* reading */
		*trans = ast_translator_build_path(*format, *rawformat);
	else
		/* writing */
		*trans = ast_translator_build_path(*rawformat, *format);
	ast_channel_unlock(chan);
	if (option_debug)
		ast_log(LOG_DEBUG, "Set channel %s to %s format %s\n", chan->name,
			direction ? "write" : "read", ast_getformatname(fmt));
	return 0;
}

int ast_set_read_format(struct ast_channel *chan, int fmt)
{
	return set_format(chan, fmt, &chan->rawreadformat, &chan->readformat,
			  &chan->readtrans, 0);
}

int ast_set_write_format(struct ast_channel *chan, int fmt)
{
	return set_format(chan, fmt, &chan->rawwriteformat, &chan->writeformat,
			  &chan->writetrans, 1);
}

struct ast_channel *__ast_request_and_dial(const char *type, int format, void *data, int timeout, int *outstate, const char *cid_num, const char *cid_name, struct outgoing_helper *oh)
{
	int dummy_outstate;
	int cause = 0;
	struct ast_channel *chan;
	int res = 0;
	
	if (outstate)
		*outstate = 0;
	else
		outstate = &dummy_outstate;	/* make outstate always a valid pointer */

	chan = ast_request(type, format, data, &cause);
	if (!chan) {
		ast_log(LOG_NOTICE, "Unable to request channel %s/%s\n", type, (char *)data);
		/* compute error and return */
		if (cause == AST_CAUSE_BUSY)
			*outstate = AST_CONTROL_BUSY;
		else if (cause == AST_CAUSE_CONGESTION)
			*outstate = AST_CONTROL_CONGESTION;
		return NULL;
	}

	if (oh) {
		if (oh->vars)	
			ast_set_variables(chan, oh->vars);
		/* XXX why is this necessary, for the parent_channel perhaps ? */
		if (!ast_strlen_zero(oh->cid_num) && !ast_strlen_zero(oh->cid_name))
			ast_set_callerid(chan, oh->cid_num, oh->cid_name, oh->cid_num);
		if (oh->parent_channel)
			ast_channel_inherit_variables(oh->parent_channel, chan);
		if (oh->account)
			ast_cdr_setaccount(chan, oh->account);	
	}
	ast_set_callerid(chan, cid_num, cid_name, cid_num);

	if (ast_call(chan, data, 0)) {	/* ast_call failed... */
		ast_log(LOG_NOTICE, "Unable to call channel %s/%s\n", type, (char *)data);
	} else {
		res = 1;	/* mark success in case chan->_state is already AST_STATE_UP */
		while (timeout && chan->_state != AST_STATE_UP) {
			struct ast_frame *f;
			res = ast_waitfor(chan, timeout);
			if (res <= 0) /* error, timeout, or done */
				break;
			if (timeout > -1)
				timeout = res;
			f = ast_read(chan);
			if (!f) {
				*outstate = AST_CONTROL_HANGUP;
				res = 0;
				break;
			}
			if (f->frametype == AST_FRAME_CONTROL) {
				switch (f->subclass) {
				case AST_CONTROL_RINGING:	/* record but keep going */
					*outstate = f->subclass;
					break;

				case AST_CONTROL_BUSY:
				case AST_CONTROL_CONGESTION:
				case AST_CONTROL_ANSWER:
					*outstate = f->subclass;
					timeout = 0;		/* trick to force exit from the while() */
					break;

				/* Ignore these */
				case AST_CONTROL_PROGRESS:
				case AST_CONTROL_PROCEEDING:
				case AST_CONTROL_HOLD:
				case AST_CONTROL_UNHOLD:
				case AST_CONTROL_VIDUPDATE:
				case -1:			/* Ignore -- just stopping indications */
					break;

				default:
					ast_log(LOG_NOTICE, "Don't know what to do with control frame %d\n", f->subclass);
				}
			}
			ast_frfree(f);
		}
	}

	/* Final fixups */
	if (oh) {
		if (!ast_strlen_zero(oh->context))
			ast_copy_string(chan->context, oh->context, sizeof(chan->context));
		if (!ast_strlen_zero(oh->exten))
			ast_copy_string(chan->exten, oh->exten, sizeof(chan->exten));
		if (oh->priority)	
			chan->priority = oh->priority;
	}
	if (chan->_state == AST_STATE_UP)
		*outstate = AST_CONTROL_ANSWER;

	if (res <= 0) {
		if (!chan->cdr && (chan->cdr = ast_cdr_alloc()))
			ast_cdr_init(chan->cdr, chan);
		if (chan->cdr) {
			char tmp[256];
			snprintf(tmp, sizeof(tmp), "%s/%s", type, (char *)data);
			ast_cdr_setapp(chan->cdr,"Dial",tmp);
			ast_cdr_update(chan);
			ast_cdr_start(chan->cdr);
			ast_cdr_end(chan->cdr);
			/* If the cause wasn't handled properly */
			if (ast_cdr_disposition(chan->cdr,chan->hangupcause))
				ast_cdr_failed(chan->cdr);
		}
		ast_hangup(chan);
		chan = NULL;
	}
	return chan;
}

struct ast_channel *ast_request_and_dial(const char *type, int format, void *data, int timeout, int *outstate, const char *cidnum, const char *cidname)
{
	return __ast_request_and_dial(type, format, data, timeout, outstate, cidnum, cidname, NULL);
}

struct ast_channel *ast_request(const char *type, int format, void *data, int *cause)
{
	struct chanlist *chan;
	struct ast_channel *c;
	int capabilities;
	int fmt;
	int res;
	int foo;
	int videoformat = format & AST_FORMAT_VIDEO_MASK;

	if (!cause)
		cause = &foo;
	*cause = AST_CAUSE_NOTDEFINED;

	if (AST_LIST_LOCK(&channels)) {
		ast_log(LOG_WARNING, "Unable to lock channel list\n");
		return NULL;
	}

	AST_LIST_TRAVERSE(&backends, chan, list) {
		if (strcasecmp(type, chan->tech->type))
			continue;

		capabilities = chan->tech->capabilities;
		fmt = format & AST_FORMAT_AUDIO_MASK;
		res = ast_translator_best_choice(&fmt, &capabilities);
		if (res < 0) {
			ast_log(LOG_WARNING, "No translator path exists for channel type %s (native %d) to %d\n", type, chan->tech->capabilities, format);
			AST_LIST_UNLOCK(&channels);
			return NULL;
		}
		AST_LIST_UNLOCK(&channels);
		if (!chan->tech->requester)
			return NULL;
		
		if (!(c = chan->tech->requester(type, capabilities | videoformat, data, cause)))
			return NULL;

		if (c->_state == AST_STATE_DOWN) {
			manager_event(EVENT_FLAG_CALL, "Newchannel",
				      "Channel: %s\r\n"
				      "State: %s\r\n"
				      "CallerID: %s\r\n"
				      "CallerIDName: %s\r\n"
				      "Uniqueid: %s\r\n",
				      c->name, ast_state2str(c->_state),
				      S_OR(c->cid.cid_num, "<unknown>"),
				      S_OR(c->cid.cid_name, "<unknown>"),
				      c->uniqueid);
		}
		return c;
	}

	ast_log(LOG_WARNING, "No channel type registered for '%s'\n", type);
	*cause = AST_CAUSE_NOSUCHDRIVER;
	AST_LIST_UNLOCK(&channels);

	return NULL;
}

int ast_call(struct ast_channel *chan, char *addr, int timeout)
{
	/* Place an outgoing call, but don't wait any longer than timeout ms before returning.
	   If the remote end does not answer within the timeout, then do NOT hang up, but
	   return anyway.  */
	int res = -1;
	/* Stop if we're a zombie or need a soft hangup */
	ast_channel_lock(chan);
	if (!ast_test_flag(chan, AST_FLAG_ZOMBIE) && !ast_check_hangup(chan)) {
		if (chan->tech->call)
			res = chan->tech->call(chan, addr, timeout);
		ast_set_flag(chan, AST_FLAG_OUTGOING);
	}
	ast_channel_unlock(chan);
	return res;
}

/*!
  \brief Transfer a call to dest, if the channel supports transfer

  Called by:
    \arg app_transfer
    \arg the manager interface
*/
int ast_transfer(struct ast_channel *chan, char *dest)
{
	int res = -1;

	/* Stop if we're a zombie or need a soft hangup */
	ast_channel_lock(chan);
	if (!ast_test_flag(chan, AST_FLAG_ZOMBIE) && !ast_check_hangup(chan)) {
		if (chan->tech->transfer) {
			res = chan->tech->transfer(chan, dest);
			if (!res)
				res = 1;
		} else
			res = 0;
	}
	ast_channel_unlock(chan);
	return res;
}

int ast_readstring(struct ast_channel *c, char *s, int len, int timeout, int ftimeout, char *enders)
{
	return ast_readstring_full(c, s, len, timeout, ftimeout, enders, -1, -1);
}

int ast_readstring_full(struct ast_channel *c, char *s, int len, int timeout, int ftimeout, char *enders, int audiofd, int ctrlfd)
{
	int pos = 0;	/* index in the buffer where we accumulate digits */
	int to = ftimeout;

	/* Stop if we're a zombie or need a soft hangup */
	if (ast_test_flag(c, AST_FLAG_ZOMBIE) || ast_check_hangup(c))
		return -1;
	if (!len)
		return -1;
	for (;;) {
		int d;
		if (c->stream) {
			d = ast_waitstream_full(c, AST_DIGIT_ANY, audiofd, ctrlfd);
			ast_stopstream(c);
			usleep(1000);
			if (!d)
				d = ast_waitfordigit_full(c, to, audiofd, ctrlfd);
		} else {
			d = ast_waitfordigit_full(c, to, audiofd, ctrlfd);
		}
		if (d < 0)
			return -1;
		if (d == 0) {
			s[pos]='\0';
			return 1;
		}
		if (d == 1) {
			s[pos]='\0';
			return 2;
		}
		if (!strchr(enders, d))
			s[pos++] = d;
		if (strchr(enders, d) || (pos >= len)) {
			s[pos]='\0';
			return 0;
		}
		to = timeout;
	}
	/* Never reached */
	return 0;
}

int ast_channel_supports_html(struct ast_channel *chan)
{
	return (chan->tech->send_html) ? 1 : 0;
}

int ast_channel_sendhtml(struct ast_channel *chan, int subclass, const char *data, int datalen)
{
	if (chan->tech->send_html)
		return chan->tech->send_html(chan, subclass, data, datalen);
	return -1;
}

int ast_channel_sendurl(struct ast_channel *chan, const char *url)
{
	return ast_channel_sendhtml(chan, AST_HTML_URL, url, strlen(url) + 1);
}

int ast_channel_make_compatible(struct ast_channel *chan, struct ast_channel *peer)
{
	int src;
	int dst;

	/* Set up translation from the chan to the peer */
	src = chan->nativeformats;
	dst = peer->nativeformats;
	if (ast_translator_best_choice(&dst, &src) < 0) {
		ast_log(LOG_WARNING, "No path to translate from %s(%d) to %s(%d)\n", chan->name, src, peer->name, dst);
		return -1;
	}

	/* if the best path is not 'pass through', then
	   transcoding is needed; if desired, force transcode path
	   to use SLINEAR between channels, but only if there is
	   no direct conversion available */
	if ((src != dst) && ast_opt_transcode_via_slin &&
	    (ast_translate_path_steps(dst, src) != 1))
		dst = AST_FORMAT_SLINEAR;
	if (ast_set_read_format(chan, dst) < 0) {
		ast_log(LOG_WARNING, "Unable to set read format on channel %s to %d\n", chan->name, dst);
		return -1;
	}
	if (ast_set_write_format(peer, dst) < 0) {
		ast_log(LOG_WARNING, "Unable to set write format on channel %s to %d\n", peer->name, dst);
		return -1;
	}

	/* Set up translation from the peer to the chan */
	src = peer->nativeformats;
	dst = chan->nativeformats;
	if (ast_translator_best_choice(&dst, &src) < 0) {
		ast_log(LOG_WARNING, "No path to translate from %s(%d) to %s(%d)\n", peer->name, src, chan->name, dst);
		return -1;
	}

	/* if the best path is not 'pass through', then
	   transcoding is needed; if desired, force transcode path
	   to use SLINEAR between channels, but only if there is
	   no direct conversion available */
	if ((src != dst) && ast_opt_transcode_via_slin &&
	    (ast_translate_path_steps(dst, src) != 1))
		dst = AST_FORMAT_SLINEAR;
	if (ast_set_read_format(peer, dst) < 0) {
		ast_log(LOG_WARNING, "Unable to set read format on channel %s to %d\n", peer->name, dst);
		return -1;
	}
	if (ast_set_write_format(chan, dst) < 0) {
		ast_log(LOG_WARNING, "Unable to set write format on channel %s to %d\n", chan->name, dst);
		return -1;
	}
	return 0;
}

int ast_channel_masquerade(struct ast_channel *original, struct ast_channel *clone)
{
	int res = -1;

	/* each of these channels may be sitting behind a channel proxy (i.e. chan_agent)
	   and if so, we don't really want to masquerade it, but its proxy */
	if (original->_bridge && (original->_bridge != ast_bridged_channel(original)))
		original = original->_bridge;

	if (clone->_bridge && (clone->_bridge != ast_bridged_channel(clone)))
		clone = clone->_bridge;

	if (original == clone) {
		ast_log(LOG_WARNING, "Can't masquerade channel '%s' into itself!\n", original->name);
		return -1;
	}
	ast_channel_lock(original);
	while(ast_channel_trylock(clone)) {
		ast_channel_unlock(original);
		usleep(1);
		ast_channel_lock(original);
	}
	ast_log(LOG_DEBUG, "Planning to masquerade channel %s into the structure of %s\n",
		clone->name, original->name);
	if (original->masq) {
		ast_log(LOG_WARNING, "%s is already going to masquerade as %s\n",
			original->masq->name, original->name);
	} else if (clone->masqr) {
		ast_log(LOG_WARNING, "%s is already going to masquerade as %s\n",
			clone->name, clone->masqr->name);
	} else {
		original->masq = clone;
		clone->masqr = original;
		ast_queue_frame(original, &ast_null_frame);
		ast_queue_frame(clone, &ast_null_frame);
		ast_log(LOG_DEBUG, "Done planning to masquerade channel %s into the structure of %s\n", clone->name, original->name);
		res = 0;
	}
	ast_channel_unlock(clone);
	ast_channel_unlock(original);
	return res;
}

void ast_change_name(struct ast_channel *chan, char *newname)
{
	manager_event(EVENT_FLAG_CALL, "Rename", "Oldname: %s\r\nNewname: %s\r\nUniqueid: %s\r\n", chan->name, newname, chan->uniqueid);
	ast_string_field_set(chan, name, newname);
}

void ast_channel_inherit_variables(const struct ast_channel *parent, struct ast_channel *child)
{
	struct ast_var_t *current, *newvar;
	const char *varname;

	AST_LIST_TRAVERSE(&parent->varshead, current, entries) {
		int vartype = 0;

		varname = ast_var_full_name(current);
		if (!varname)
			continue;

		if (varname[0] == '_') {
			vartype = 1;
			if (varname[1] == '_')
				vartype = 2;
		}

		switch (vartype) {
		case 1:
			newvar = ast_var_assign(&varname[1], ast_var_value(current));
			if (newvar) {
				AST_LIST_INSERT_TAIL(&child->varshead, newvar, entries);
				if (option_debug)
					ast_log(LOG_DEBUG, "Copying soft-transferable variable %s.\n", ast_var_name(newvar));
			}
			break;
		case 2:
			newvar = ast_var_assign(ast_var_full_name(current), ast_var_value(current));
			if (newvar) {
				AST_LIST_INSERT_TAIL(&child->varshead, newvar, entries);
				if (option_debug)
					ast_log(LOG_DEBUG, "Copying hard-transferable variable %s.\n", ast_var_name(newvar));
			}
			break;
		default:
			if (option_debug)
				ast_log(LOG_DEBUG, "Not copying variable %s.\n", ast_var_name(current));
			break;
		}
	}
}

/*!
  \brief Clone channel variables from 'clone' channel into 'original' channel

  All variables except those related to app_groupcount are cloned.
  Variables are actually _removed_ from 'clone' channel, presumably
  because it will subsequently be destroyed.

  \note Assumes locks will be in place on both channels when called.
*/
static void clone_variables(struct ast_channel *original, struct ast_channel *clone)
{
	struct ast_var_t *varptr;

	/* we need to remove all app_groupcount related variables from the original
	   channel before merging in the clone's variables; any groups assigned to the
	   original channel should be released, only those assigned to the clone
	   should remain
	*/

	AST_LIST_TRAVERSE_SAFE_BEGIN(&original->varshead, varptr, entries) {
		if (!strncmp(ast_var_name(varptr), GROUP_CATEGORY_PREFIX, strlen(GROUP_CATEGORY_PREFIX))) {
			AST_LIST_REMOVE(&original->varshead, varptr, entries);
			ast_var_delete(varptr);
		}
	}
	AST_LIST_TRAVERSE_SAFE_END;

	/* Append variables from clone channel into original channel */
	/* XXX Is this always correct?  We have to in order to keep MACROS working XXX */
	if (AST_LIST_FIRST(&clone->varshead))
		AST_LIST_INSERT_TAIL(&original->varshead, AST_LIST_FIRST(&clone->varshead), entries);
}

/*!
  \brief Masquerade a channel

  \note Assumes channel will be locked when called
*/
int ast_do_masquerade(struct ast_channel *original)
{
	int x,i;
	int res=0;
	int origstate;
	struct ast_frame *cur, *prev;
	const struct ast_channel_tech *t;
	void *t_pvt;
	struct ast_callerid tmpcid;
	struct ast_channel *clone = original->masq;
	int rformat = original->readformat;
	int wformat = original->writeformat;
	char newn[100];
	char orig[100];
	char masqn[100];
	char zombn[100];

	if (option_debug > 3)
		ast_log(LOG_DEBUG, "Actually Masquerading %s(%d) into the structure of %s(%d)\n",
			clone->name, clone->_state, original->name, original->_state);