app_rpt: Correct VOX operation for autopatch

This change restores the operation of the autopatch VOX function.

Changes were made in #363 to get the autopatch working.  Part of those changes did not correctly address the operation of the VOX channel.  This change removes some of those changes and restores the operation of the VOX channel.

For the VOX channel to work properly, this change along with changes to the DAHDI driver are required.  The changes to the DAHDI driver are located at https://github.com/KB4MDD/dahdi-linux

We will be attempting to get these changes into the main DAHDI channel.

apps/app_rpt/rpt_bridging.c

@@ -417,29 +417,20 @@ static int *dahdi_confno(struct rpt *myrpt, enum rpt_conf_type type)
 }
 
 /*!
- * \brief Get the conference number of a DAHDI channel
+ * \brief Get the channel number of a DAHDI channel
  * \param chan DAHDI channel
  * \retval -1 on failure, conference number on success
  */
-static int dahdi_conf_fd_confno(struct ast_channel *chan)
-{
-	struct dahdi_confinfo ci;
-	ci.chan = 0;
-	ci.confno = 0;
-	ci.confmode = 0;
-
-	/* This routine previously called DAHDI_CHANNO.  After testing, we 
-	 * determined that DAHDI_CHANNO is actually returning the channel number, 
-	 * instead of the conference number.  In some cases the channel number
-	 * was same as the conference number.  Since it was not accurate in
-	 * all cases, it was switched to DAHDI_GETCONF.
-	 */
-	if (ioctl(ast_channel_fd(chan, 0), DAHDI_GETCONF, &ci)) {
-		ast_log(LOG_WARNING, "DAHDI_GETCONF failed: %s\n", strerror(errno));
+static int dahdi_conf_get_channo(struct ast_channel *chan)
+{
+	struct dahdi_confinfo ci = {0};
+
+	if (ioctl(ast_channel_fd(chan, 0), DAHDI_CHANNO, &ci.chan)) {
+		ast_log(LOG_WARNING, "DAHDI_CHANNO failed: %s\n", strerror(errno));
 		return -1;
 	}
 
-	return ci.confno;
+	return ci.chan;
 }
 
 int __rpt_conf_create(struct ast_channel *chan, struct rpt *myrpt, enum rpt_conf_type type, enum rpt_conf_flags flags, const char *file, int line)
@@ -494,7 +485,7 @@ int rpt_call_bridge_setup(struct rpt *myrpt, struct ast_channel *mychannel, stru
 	}
 
 	/* get its conference number */
-	res = dahdi_conf_fd_confno(mychannel);
+	res = dahdi_conf_get_channo(mychannel);
 	if (res < 0) {
 		ast_log(LOG_WARNING, "Unable to get autopatch channel number\n");
 		ast_hangup(mychannel);
@@ -503,12 +494,16 @@ int rpt_call_bridge_setup(struct rpt *myrpt, struct ast_channel *mychannel, stru
 
 	/* put vox channel monitoring on the channel  
 	 *
-	 * The conference flags were originally DAHDI_CONF_MONITOR.  This 
-	 * setting caused dahdi_conf_add to return EINVAL.  The  flags
-	 * RPT_CONF_CONF | RPT_CONF_LISTENER permits the vox channel to 
-	 * join the conference.
+	 * This uses the internal DAHDI channel number to create the 
+	 * monitor conference.  This code will hang here when trying to 
+	 * join the conference when the underlying version of DAHDI in use
+	 * is missing a patch that allows the DAHDI_CONF_MONITOR option
+	 * to monitor a pseudo channel.  This patch prevents the hardware
+	 * pre-echo routines from acting on a pseudo channel.  It also
+	 * prevents the DAHDI check conference routine from acting
+	 * on a channel number being used as a conference.
 	 */
-	if (dahdi_conf_add(myrpt->voxchannel, res, RPT_CONF_CONF | RPT_CONF_LISTENER)) {
+	if (dahdi_conf_add(myrpt->voxchannel, res, DAHDI_CONF_MONITOR)) {
 		ast_hangup(mychannel);
 		return -1;
 	}
@@ -520,7 +515,7 @@ int rpt_mon_setup(struct rpt *myrpt)
 	int res;
 
 	if (!IS_PSEUDO(myrpt->txchannel) && myrpt->dahditxchannel == myrpt->txchannel) {
-		int confno = dahdi_conf_fd_confno(myrpt->txchannel); /* get tx channel's port number */
+		int confno = dahdi_conf_get_channo(myrpt->txchannel); /* get tx channel's port number */
 		if (confno < 0) {
 			return -1;
 		}