--- channel.c	2004-05-18 16:29:27.000000000 -0400
+++ channel.c.merged	2004-05-18 16:44:16.000000000 -0400
@@ -276,20 +276,21 @@
 	struct varshead *headp;        
 	        
 	
 	/* If shutting down, don't allocate any new channels */
 	if (shutting_down)
 		return NULL;
 	ast_mutex_lock(&chlock);
 	tmp = malloc(sizeof(struct ast_channel));
 	if (tmp) {
 		memset(tmp, 0, sizeof(struct ast_channel));
+		tmp->used_by_dual_xfer=0;
 		pvt = malloc(sizeof(struct ast_channel_pvt));
 		if (pvt) {
 			memset(pvt, 0, sizeof(struct ast_channel_pvt));
 			tmp->sched = sched_context_create();
 			if (tmp->sched) {
 				for (x=0;x<AST_MAX_FDS - 1;x++)
 					tmp->fds[x] = -1;
 #ifdef ZAPTEL_OPTIMIZATIONS
 				tmp->timingfd = open("/dev/zap/timer", O_RDWR);
 				if (tmp->timingfd > -1) {
@@ -621,21 +622,28 @@
 	clone->pvt->readtrans = NULL;
 	clone->pvt->rawwriteformat = clone->nativeformats;
 	clone->pvt->rawreadformat = clone->nativeformats;
 }
 
 int ast_hangup(struct ast_channel *chan)
 {
 	int res = 0;
 	/* Don't actually hang up a channel that will masquerade as someone else, or
 	   if someone is going to masquerade as us */
+
 	ast_mutex_lock(&chan->lock);
+
+        if (chan->used_by_dual_xfer==1) {
+	      ast_mutex_unlock(&chan->lock);
+              return 0;
+        }
+
 	if (chan->masq) {
 		if (ast_do_masquerade(chan)) 
 			ast_log(LOG_WARNING, "Failed to perform masquerade\n");
 	}
 
 	if (chan->masq) {
 		ast_log(LOG_WARNING, "%s getting hung up, but someone is trying to masq into us?!?\n", chan->name);
 		ast_mutex_unlock(&chan->lock);
 		return 0;
 	}