Merged revisions 206487 via svnmerge from

https://origsvn.digium.com/svn/asterisk/branches/1.4

........
  r206487 | rmudgett | 2009-07-14 11:44:47 -0500 (Tue, 14 Jul 2009) | 28 lines
  
  Fixes several call transfer issues with chan_misdn.
  
  *  issue #14355 - Crash if attempt to transfer a call to an application.
  Masquerade the other pair of the four asterisk channels involved in the
  two calls.  The held call already must be a bridged call (not an
  applicaton) or it would have been rejected.
  
  *  issue #14692 - Held calls are not automatically cleared after transfer.
  Allow the core to initate disconnect of held calls to the ISDN port.  This
  also fixes a similar case where the party on hold hangs up before being
  transferred or taken off hold.
  
  *  JIRA ABE-1903 - Orphaned held calls left in music-on-hold.
  Do not simply block passing the hangup event on held calls to asterisk
  core.
  
  *  Fixed to allow held calls to be transferred to ringing calls.
  Previously, held calls could only be transferred to connected calls.
  *  Eliminated unused call states to simplify hangup code.
  *  Eliminated most uses of "holded" because it is not a word.
  
  (closes issue #14355)
  (closes issue #14692)
  Reported by: sodom
  Patches:
        misdn_xfer_v14_r205839.patch uploaded by rmudgett (license 664)
  Tested by: rmudgett
........


git-svn-id: http://svn.digium.com/svn/asterisk/trunk@206489 f38db490-d61c-443f-a65b-d21fe96a405b

3 files changed, 394 insertions, 283 deletions

diff --git a/channels/chan_misdn.c b/channels/chan_misdn.c
index 5be536abf..3a5a5b4f1 100644
--- a/channels/chan_misdn.c
+++ b/channels/chan_misdn.c
@@ -305,15 +305,8 @@ enum misdn_chan_state {
 	MISDN_ALERTING,            /*!< when Alerting */
 	MISDN_BUSY,                /*!< when BUSY */
 	MISDN_CONNECTED,           /*!< when connected */
-	MISDN_PRECONNECTED,        /*!< when connected (Noone sets this state) */
 	MISDN_DISCONNECTED,        /*!< when connected */
-	MISDN_RELEASED,            /*!< when connected */
-	MISDN_BRIDGED,             /*!< when bridged */
 	MISDN_CLEANING,            /*!< when hangup from * but we were connected before */
-	MISDN_HUNGUP_FROM_MISDN,   /*!< when DISCONNECT/RELEASE/REL_COMP came from misdn */
-	MISDN_HUNGUP_FROM_AST,     /*!< when DISCONNECT/RELEASE/REL_COMP came out of misdn_hangup */
-	MISDN_HOLDED,              /*!< when on hold */
-	MISDN_HOLD_DISCONNECT,     /*!< when on hold */
 };
 
 /*! Asterisk created the channel (outgoing call) */
@@ -321,15 +314,25 @@ enum misdn_chan_state {
 /*! mISDN created the channel (incoming call) */
 #define ORG_MISDN 2
 
+enum misdn_hold_state {
+	MISDN_HOLD_IDLE,		/*!< HOLD not active */
+	MISDN_HOLD_ACTIVE,		/*!< Call is held */
+	MISDN_HOLD_TRANSFER,	/*!< Held call is being transferred */
+	MISDN_HOLD_DISCONNECT,	/*!< Held call is being disconnected */
+};
 struct hold_info {
 	/*!
-	 * \brief Logical port the channel call record is HOLDED on
+	 * \brief Call HOLD state.
+	 */
+	enum misdn_hold_state state;
+	/*!
+	 * \brief Logical port the channel call record is HELD on
 	 * because the B channel is no longer associated.
 	 */
 	int port;
 
 	/*!
-	 * \brief Original B channel number the HOLDED call was using.
+	 * \brief Original B channel number the HELD call was using.
 	 * \note Used only for debug display messages.
 	 */
 	int channel;
@@ -501,13 +504,13 @@ struct chan_list {
 #endif	/* defined(AST_MISDN_ENHANCEMENTS) */
 
 	/*!
-	 * \brief HOLDED channel information
+	 * \brief HELD channel call information
 	 */
-	struct hold_info hold_info;
+	struct hold_info hold;
 
 	/*!
 	 * \brief From associated B channel: Layer 3 process ID
-	 * \note Used to find the HOLDED channel call record when retrieving a call.
+	 * \note Used to find the HELD channel call record when retrieving a call.
 	 */
 	unsigned int l3id;
 
@@ -662,7 +665,6 @@ static void chan_misdn_log(int level, int port, char *tmpl, ...)
 static struct ast_channel *misdn_new(struct chan_list *cl, int state,  char *exten, char *callerid, int format, const char *linkedid, int port, int c);
 static void send_digit_to_chan(struct chan_list *cl, char digit);
 
-static void hangup_chan(struct chan_list *ch);
 static int pbx_start_chan(struct chan_list *ch);
 
 #define MISDN_ASTERISK_TECH_PVT(ast) ast->tech_pvt
@@ -702,12 +704,13 @@ static struct chan_list *find_chan_by_bc(struct chan_list *list, struct misdn_bc
 static struct chan_list *find_chan_by_pid(struct chan_list *list, int pid);
 
 static int dialtone_indicate(struct chan_list *cl);
-static int hanguptone_indicate(struct chan_list *cl);
+static void hanguptone_indicate(struct chan_list *cl);
 static int stop_indicate(struct chan_list *cl);
 
 static int start_bc_tones(struct chan_list *cl);
 static int stop_bc_tones(struct chan_list *cl);
-static void release_chan(struct misdn_bchannel *bc);
+static void release_chan_early(struct chan_list *ch);
+static void release_chan(struct chan_list *ch, struct misdn_bchannel *bc);
 
 #if defined(AST_MISDN_ENHANCEMENTS)
 static const char misdn_command_name[] = "misdn_command";
@@ -4039,15 +4042,8 @@ static const struct state_struct state_array[] = {
 	{ MISDN_ALERTING,            "ALERTING" },            /* when Alerting */
 	{ MISDN_BUSY,                "BUSY" },                /* when BUSY */
 	{ MISDN_CONNECTED,           "CONNECTED" },           /* when connected */
-	{ MISDN_PRECONNECTED,        "PRECONNECTED" },        /* when connected */
 	{ MISDN_DISCONNECTED,        "DISCONNECTED" },        /* when connected */
-	{ MISDN_RELEASED,            "RELEASED" },            /* when connected */
-	{ MISDN_BRIDGED,             "BRIDGED" },             /* when bridged */
 	{ MISDN_CLEANING,            "CLEANING" },            /* when hangup from * but we were connected before */
-	{ MISDN_HUNGUP_FROM_MISDN,   "HUNGUP_FROM_MISDN" },   /* when DISCONNECT/RELEASE/REL_COMP came from misdn */
-	{ MISDN_HOLDED,              "HOLDED" },              /* when DISCONNECT/RELEASE/REL_COMP came from misdn */
-	{ MISDN_HOLD_DISCONNECT,     "HOLD_DISCONNECT" },     /* when DISCONNECT/RELEASE/REL_COMP came from misdn */
-	{ MISDN_HUNGUP_FROM_AST,     "HUNGUP_FROM_AST" },     /* when DISCONNECT/RELEASE/REL_COMP came out of misdn_hangup */
 /* *INDENT-ON* */
 };
 
@@ -4218,8 +4214,8 @@ static char *handle_cli_misdn_show_channels(struct ast_cli_entry *e, int cmd, st
 		if (bc) {
 			print_bc_info(a->fd, help, bc);
 		} else {
-			if (help->state == MISDN_HOLDED) {
-				ast_cli(a->fd, "ITS A HOLDED BC:\n");
+			if (help->hold.state != MISDN_HOLD_IDLE) {
+				ast_cli(a->fd, "ITS A HELD CALL BC:\n");
 				ast_cli(a->fd, " --> l3_id: %x\n"
 					" --> dialed:%s\n"
 					" --> caller:\"%s\" <%s>\n"
@@ -4229,8 +4225,8 @@ static char *handle_cli_misdn_show_channels(struct ast_cli_entry *e, int cmd, st
 					ast->exten,
 					ast->cid.cid_name ? ast->cid.cid_name : "",
 					ast->cid.cid_num ? ast->cid.cid_num : "",
-					help->hold_info.port,
-					help->hold_info.channel
+					help->hold.port,
+					help->hold.channel
 					);
 			} else {
 				ast_cli(a->fd, "* Channel in unknown STATE !!! Exten:%s, Callerid:%s\n", ast->exten, ast->cid.cid_num);
@@ -6662,12 +6658,18 @@ static int misdn_indication(struct ast_channel *ast, int cond, const void *data,
 	}
 
 	if (!p->bc) {
-		chan_misdn_log(1, 0, "* IND : Indication from %s\n", ast->exten);
-		ast_log(LOG_WARNING, "Private Pointer but no bc ?\n");
+		if (p->hold.state == MISDN_HOLD_IDLE) {
+			chan_misdn_log(1, 0, "* IND : Indication [%d] ignored on %s\n", cond,
+				ast->name);
+			ast_log(LOG_WARNING, "Private Pointer but no bc ?\n");
+		} else {
+			chan_misdn_log(1, 0, "* IND : Indication [%d] ignored on hold %s\n",
+				cond, ast->name);
+		}
 		return -1;
 	}
 
-	chan_misdn_log(5, p->bc->port, "* IND : Indication [%d] from %s\n", cond, ast->exten);
+	chan_misdn_log(5, p->bc->port, "* IND : Indication [%d] on %s\n\n", cond, ast->name);
 
 	switch (cond) {
 	case AST_CONTROL_BUSY:
@@ -6778,7 +6780,7 @@ static int misdn_indication(struct ast_channel *ast, int cond, const void *data,
 		break;
 	default:
 		chan_misdn_log(1, p->bc->port, " --> * Unknown Indication:%d pid:%d\n", cond, p->bc->pid);
-		break;
+		return -1;
 	}
 
 	return 0;
@@ -6787,91 +6789,79 @@ static int misdn_indication(struct ast_channel *ast, int cond, const void *data,
 static int misdn_hangup(struct ast_channel *ast)
 {
 	struct chan_list *p;
-	struct misdn_bchannel *bc = NULL;
-	const char *varcause = NULL;
-
-	ast_debug(1, "misdn_hangup(%s)\n", ast->name);
+	struct misdn_bchannel *bc;
+	const char *var;
 
 	if (!ast || !(p = MISDN_ASTERISK_TECH_PVT(ast))) {
 		return -1;
 	}
+	MISDN_ASTERISK_TECH_PVT(ast) = NULL;
 
-	if (!p) {
-		chan_misdn_log(3, 0, "misdn_hangup called, without chan_list obj.\n");
-		return 0 ;
-	}
-
-	bc = p->bc;
-
-	if (bc) {
-		const char *tmp;
+	ast_debug(1, "misdn_hangup(%s)\n", ast->name);
 
-		ast_channel_lock(ast);
-		tmp = pbx_builtin_getvar_helper(ast, "MISDN_USERUSER");
-		if (tmp) {
-			ast_log(LOG_NOTICE, "MISDN_USERUSER: %s\n", tmp);
-			strcpy(bc->uu, tmp);
-			bc->uulen = strlen(bc->uu);
+	if (p->hold.state == MISDN_HOLD_IDLE) {
+		bc = p->bc;
+	} else {
+		p->hold.state = MISDN_HOLD_DISCONNECT;
+		bc = misdn_lib_find_held_bc(p->hold.port, p->l3id);
+		if (!bc) {
+			chan_misdn_log(4, p->hold.port,
+				"misdn_hangup: Could not find held bc for (%s)\n", ast->name);
+			release_chan_early(p);
+			return 0;
 		}
-		ast_channel_unlock(ast);
 	}
 
-	MISDN_ASTERISK_TECH_PVT(ast) = NULL;
-	p->ast = NULL;
-
-	if (ast->_state == AST_STATE_RESERVED ||
-		p->state == MISDN_NOTHING ||
-		p->state == MISDN_HOLDED ||
-		p->state == MISDN_HOLD_DISCONNECT) {
-
-CLEAN_CH:
+	if (ast->_state == AST_STATE_RESERVED || p->state == MISDN_NOTHING) {
 		/* between request and call */
 		ast_debug(1, "State Reserved (or nothing) => chanIsAvail\n");
-		MISDN_ASTERISK_TECH_PVT(ast) = NULL;
-
-		ast_mutex_lock(&release_lock);
-		cl_dequeue_chan(&cl_te, p);
-		close(p->pipe[0]);
-		close(p->pipe[1]);
-		ast_free(p);
-		ast_mutex_unlock(&release_lock);
-
+		release_chan_early(p);
 		if (bc) {
 			misdn_lib_release(bc);
 		}
-
 		return 0;
 	}
-
 	if (!bc) {
-		ast_log(LOG_WARNING, "Hangup with private but no bc ? state:%s l3id:%x\n", misdn_get_ch_state(p), p->l3id);
-		goto CLEAN_CH;
+		ast_log(LOG_WARNING, "Hangup with private but no bc ? state:%s l3id:%x\n",
+			misdn_get_ch_state(p), p->l3id);
+		release_chan_early(p);
+		return 0;
 	}
 
-
+	p->ast = NULL;
 	p->need_hangup = 0;
 	p->need_queue_hangup = 0;
 	p->need_busy = 0;
 
-
-	if (!p->bc->nt) {
+	if (!bc->nt) {
 		stop_bc_tones(p);
 	}
 
 	bc->out_cause = ast->hangupcause ? ast->hangupcause : AST_CAUSE_NORMAL_CLEARING;
 
 	ast_channel_lock(ast);
-	if ((varcause = pbx_builtin_getvar_helper(ast, "HANGUPCAUSE")) ||
-		(varcause = pbx_builtin_getvar_helper(ast, "PRI_CAUSE"))) {
-		int tmpcause = atoi(varcause);
+	var = pbx_builtin_getvar_helper(ast, "HANGUPCAUSE");
+	if (!var) {
+		var = pbx_builtin_getvar_helper(ast, "PRI_CAUSE");
+	}
+	if (var) {
+		int tmpcause;
 
+		tmpcause = atoi(var);
 		bc->out_cause = tmpcause ? tmpcause : AST_CAUSE_NORMAL_CLEARING;
 	}
+
+	var = pbx_builtin_getvar_helper(ast, "MISDN_USERUSER");
+	if (var) {
+		ast_log(LOG_NOTICE, "MISDN_USERUSER: %s\n", var);
+		ast_copy_string(bc->uu, var, sizeof(bc->uu));
+		bc->uulen = strlen(bc->uu);
+	}
 	ast_channel_unlock(ast);
 
 	chan_misdn_log(1, bc->port,
 		"* IND : HANGUP\tpid:%d context:%s dialed:%s caller:\"%s\" <%s> State:%s\n",
-		p->bc ? p->bc->pid : -1,
+		bc->pid,
 		ast->context,
 		ast->exten,
 		ast->cid.cid_name ? ast->cid.cid_name : "",
@@ -6883,27 +6873,29 @@ CLEAN_CH:
 
 	switch (p->state) {
 	case MISDN_INCOMING_SETUP:
-		p->state = MISDN_CLEANING;
-		/* This is the only place in misdn_hangup, where we
-		 * can call release_chan, else it might create lot's of trouble
-		 * */
+		/*
+		 * This is the only place in misdn_hangup, where we
+		 * can call release_chan, else it might create a lot of trouble.
+		 */
 		ast_log(LOG_NOTICE, "release channel, in INCOMING_SETUP state.. no other events happened\n");
-		release_chan(bc);
+		release_chan(p, bc);
 		misdn_lib_send_event(bc, EVENT_RELEASE_COMPLETE);
-		break;
-	case MISDN_HOLDED:
+		return 0;
 	case MISDN_DIALING:
-		start_bc_tones(p);
-		hanguptone_indicate(p);
+		if (p->hold.state == MISDN_HOLD_IDLE) {
+			start_bc_tones(p);
+			hanguptone_indicate(p);
+		}
 
-		p->state = MISDN_CLEANING;
 		if (bc->need_disconnect) {
 			misdn_lib_send_event(bc, EVENT_DISCONNECT);
 		}
 		break;
 	case MISDN_CALLING_ACKNOWLEDGE:
-		start_bc_tones(p);
-		hanguptone_indicate(p);
+		if (p->hold.state == MISDN_HOLD_IDLE) {
+			start_bc_tones(p);
+			hanguptone_indicate(p);
+		}
 
 		if (bc->need_disconnect) {
 			misdn_lib_send_event(bc, EVENT_DISCONNECT);
@@ -6914,79 +6906,53 @@ CLEAN_CH:
 	case MISDN_ALERTING:
 	case MISDN_PROGRESS:
 	case MISDN_PROCEEDING:
-		if (p->originator != ORG_AST) {
+		if (p->originator != ORG_AST && p->hold.state == MISDN_HOLD_IDLE) {
 			hanguptone_indicate(p);
 		}
 
-		/*p->state=MISDN_CLEANING;*/
 		if (bc->need_disconnect) {
 			misdn_lib_send_event(bc, EVENT_DISCONNECT);
 		}
 		break;
 	case MISDN_CONNECTED:
-	case MISDN_PRECONNECTED:
 		/*  Alerting or Disconnect */
-		if (p->bc->nt) {
+		if (bc->nt && p->hold.state == MISDN_HOLD_IDLE) {
 			start_bc_tones(p);
 			hanguptone_indicate(p);
-			p->bc->progress_indicator = INFO_PI_INBAND_AVAILABLE;
+			bc->progress_indicator = INFO_PI_INBAND_AVAILABLE;
 		}
 		if (bc->need_disconnect) {
 			misdn_lib_send_event(bc, EVENT_DISCONNECT);
 		}
-
-		/*p->state=MISDN_CLEANING;*/
 		break;
 	case MISDN_DISCONNECTED:
 		if (bc->need_release) {
 			misdn_lib_send_event(bc, EVENT_RELEASE);
 		}
-		p->state = MISDN_CLEANING; /* MISDN_HUNGUP_FROM_AST; */
 		break;
 
-	case MISDN_RELEASED:
 	case MISDN_CLEANING:
-		p->state = MISDN_CLEANING;
-		break;
+		return 0;
 
 	case MISDN_BUSY:
 		break;
-
-	case MISDN_HOLD_DISCONNECT:
-		/* need to send release here */
-		chan_misdn_log(1, bc->port, " --> cause %d\n", bc->cause);
-		chan_misdn_log(1, bc->port, " --> out_cause %d\n", bc->out_cause);
-
-		bc->out_cause = -1;
-		if (bc->need_release) {
-			misdn_lib_send_event(bc, EVENT_RELEASE);
-		}
-		p->state = MISDN_CLEANING;
-		break;
 	default:
 		if (bc->nt) {
 			bc->out_cause = -1;
 			if (bc->need_release) {
 				misdn_lib_send_event(bc, EVENT_RELEASE);
 			}
-			p->state = MISDN_CLEANING;
 		} else {
 			if (bc->need_disconnect) {
 				misdn_lib_send_event(bc, EVENT_DISCONNECT);
 			}
 		}
+		break;
 	}
 
 	p->state = MISDN_CLEANING;
-
-#if defined(AST_MISDN_ENHANCEMENTS)
-	if (p->peer) {
-		ao2_ref(p->peer, -1);
-		p->peer = NULL;
-	}
-#endif /* AST_MISDN_ENHANCEMENTS */
-
-	chan_misdn_log(3, bc->port, " --> Channel: %s hanguped new state:%s\n", ast->name, misdn_get_ch_state(p));
+	chan_misdn_log(3, bc->port, " --> Channel: %s hungup new state:%s\n", ast->name,
+		misdn_get_ch_state(p));
 
 	return 0;
 }
@@ -7082,7 +7048,7 @@ static struct ast_frame *misdn_read(struct ast_channel *ast)
 		return NULL;
 	}
 
-	if (!tmp->bc && !(tmp->state == MISDN_HOLDED)) {
+	if (!tmp->bc && tmp->hold.state == MISDN_HOLD_IDLE) {
 		chan_misdn_log(1, 0, "misdn_read called without bc\n");
 		return NULL;
 	}
@@ -7164,8 +7130,8 @@ static int misdn_write(struct ast_channel *ast, struct ast_frame *frame)
 		return -1;
 	}
 
-	if (ch->state == MISDN_HOLDED) {
-		chan_misdn_log(7, 0, "misdn_write: Returning because holded\n");
+	if (ch->hold.state != MISDN_HOLD_IDLE) {
+		chan_misdn_log(7, 0, "misdn_write: Returning because hold active\n");
 		return 0;
 	}
 
@@ -7398,10 +7364,9 @@ static int dialtone_indicate(struct chan_list *cl)
 	return 0;
 }
 
-static int hanguptone_indicate(struct chan_list *cl)
+static void hanguptone_indicate(struct chan_list *cl)
 {
 	misdn_lib_send_tone(cl->bc, TONE_HANGUP);
-	return 0;
 }
 
 static int stop_indicate(struct chan_list *cl)
@@ -7903,7 +7868,7 @@ static struct chan_list *find_chan_by_pid(struct chan_list *list, int pid)
 	return NULL;
 }
 
-static struct chan_list *find_holded(struct chan_list *list, struct misdn_bchannel *bc)
+static struct chan_list *find_hold_call(struct chan_list *list, struct misdn_bchannel *bc)
 {
 	struct chan_list *help = list;
 
@@ -7911,20 +7876,19 @@ static struct chan_list *find_holded(struct chan_list *list, struct misdn_bchann
 		return NULL;
 	}
 
-	chan_misdn_log(6, bc->port, "$$$ find_holded: channel:%d dialed:%s caller:\"%s\" <%s>\n",
+	chan_misdn_log(6, bc->port, "$$$ find_hold_call: channel:%d dialed:%s caller:\"%s\" <%s>\n",
 		bc->channel,
 		bc->dialed.number,
 		bc->caller.name,
 		bc->caller.number);
 	for (; help; help = help->next) {
-		chan_misdn_log(4, bc->port, "$$$ find_holded: --> holded:%d channel:%d\n", help->state == MISDN_HOLDED, help->hold_info.channel);
-		if ((help->state == MISDN_HOLDED) &&
-			(help->hold_info.port == bc->port)) {
+		chan_misdn_log(4, bc->port, "$$$ find_hold_call: --> hold:%d channel:%d\n", help->hold.state, help->hold.channel);
+		if (help->hold.state == MISDN_HOLD_ACTIVE && help->hold.port == bc->port) {
 			return help;
 		}
 	}
 	chan_misdn_log(6, bc->port,
-		"$$$ find_holded: No channel found for dialed:%s caller:\"%s\" <%s>\n",
+		"$$$ find_hold_call: No channel found for dialed:%s caller:\"%s\" <%s>\n",
 		bc->dialed.number,
 		bc->caller.name,
 		bc->caller.number);
@@ -7933,13 +7897,12 @@ static struct chan_list *find_holded(struct chan_list *list, struct misdn_bchann
 }
 
 
-static struct chan_list *find_holded_l3(struct chan_list *list, unsigned long l3_id, int w)
+static struct chan_list *find_hold_call_l3(struct chan_list *list, unsigned long l3_id)
 {
 	struct chan_list *help = list;
 
 	for (; help; help = help->next) {
-		if ((help->state == MISDN_HOLDED) &&
-			(help->l3id == l3_id)) {
+		if (help->hold.state != MISDN_HOLD_IDLE && help->l3id == l3_id) {
 			return help;
 		}
 	}
@@ -7947,6 +7910,42 @@ static struct chan_list *find_holded_l3(struct chan_list *list, unsigned long l3
 	return NULL;
 }
 
+#define TRANSFER_ON_HELD_CALL_HANGUP 1
+#if defined(TRANSFER_ON_HELD_CALL_HANGUP)
+/*!
+ * \internal
+ * \brief Find a suitable active call to go with a held call so we could try a transfer.
+ *
+ * \param list Channel list.
+ * \param bc B channel record.
+ *
+ * \return Found call record or NULL.
+ *
+ * \note There could be a possibility where we find the wrong active call to transfer.
+ * This concern is mitigated by the fact that there could be at most one other call
+ * on a PTMP BRI link to another device.  Maybe the l3_id could help in locating an
+ * active call on the same TEI?
+ */
+static struct chan_list *find_hold_active_call(struct chan_list *list, struct misdn_bchannel *bc)
+{
+	for (; list; list = list->next) {
+		if (list->hold.state == MISDN_HOLD_IDLE && list->bc && list->bc->port == bc->port
+			&& list->ast) {
+			switch (list->state) {
+			case MISDN_PROCEEDING:
+			case MISDN_PROGRESS:
+			case MISDN_ALERTING:
+			case MISDN_CONNECTED:
+				return list;
+			default:
+				break;
+			}
+		}
+	}
+	return NULL;
+}
+#endif	/* defined(TRANSFER_ON_HELD_CALL_HANGUP) */
+
 static void cl_queue_chan(struct chan_list **list, struct chan_list *chan)
 {
 	chan_misdn_log(4, chan->bc ? chan->bc->port : 0, "* Queuing chan %p\n", chan);
@@ -8009,7 +8008,7 @@ static int pbx_start_chan(struct chan_list *ch)
 	return ret;
 }
 
-static void hangup_chan(struct chan_list *ch)
+static void hangup_chan(struct chan_list *ch, struct misdn_bchannel *bc)
 {
 	int port;
 
@@ -8018,15 +8017,15 @@ static void hangup_chan(struct chan_list *ch)
 		return;
 	}
 
-	port = ch->bc ? ch->bc->port : 0;
+	port = bc->port;
 	cb_log(5, port, "hangup_chan called\n");
 
 	if (ch->need_hangup) {
 		cb_log(2, port, " --> hangup\n");
-		send_cause2ast(ch->ast, ch->bc, ch);
 		ch->need_hangup = 0;
 		ch->need_queue_hangup = 0;
 		if (ch->ast) {
+			send_cause2ast(ch->ast, bc, ch);
 			ast_hangup(ch->ast);
 		}
 		return;
@@ -8038,33 +8037,43 @@ static void hangup_chan(struct chan_list *ch)
 
 	ch->need_queue_hangup = 0;
 	if (ch->ast) {
-		send_cause2ast(ch->ast, ch->bc, ch);
-
-		if (ch->ast) {
-			ast_queue_hangup_with_cause(ch->ast, ch->bc->cause);
-		}
+		send_cause2ast(ch->ast, bc, ch);
+		ast_queue_hangup_with_cause(ch->ast, bc->cause);
 		cb_log(2, port, " --> queue_hangup\n");
 	} else {
 		cb_log(1, port, "Cannot hangup chan, no ast\n");
 	}
 }
 
-/** Isdn asks us to release channel, pendant to misdn_hangup **/
-static void release_chan(struct misdn_bchannel *bc)
+/*!
+ * \internal
+ * \brief ISDN asked us to release channel, pendant to misdn_hangup.
+ *
+ * \param ch Call channel record to release.
+ * \param bc Current B channel record associated with ch.
+ *
+ * \return Nothing
+ *
+ * \note ch must not be referenced after calling.
+ */
+static void release_chan(struct chan_list *ch, struct misdn_bchannel *bc)
 {
-	struct chan_list *ch;
 	struct ast_channel *ast;
 
+	ch->state = MISDN_CLEANING;
+
 	ast_mutex_lock(&release_lock);
 
-	ch = find_chan_by_bc(cl_te, bc);
-	if (!ch) {
-		chan_misdn_log(1, bc->port, "release_chan: Ch not found!\n");
-		ast_mutex_unlock(&release_lock);
-		return;
+#if defined(AST_MISDN_ENHANCEMENTS)
+	if (ch->peer) {
+		ao2_ref(ch->peer, -1);
+		ch->peer = NULL;
 	}
+#endif /* AST_MISDN_ENHANCEMENTS */
+
+	cl_dequeue_chan(&cl_te, ch);
 
-	chan_misdn_log(5, bc->port, "release_chan: bc with l3id: %x\n", bc->l3_id);
+	chan_misdn_log(5, bc->port, "release_chan: bc with pid:%d l3id: %x\n", bc->pid, bc->l3_id);
 
 	/* releasing jitterbuffer */
 	if (ch->jb) {
@@ -8094,17 +8103,15 @@ static void release_chan(struct misdn_bchannel *bc)
 	close(ch->pipe[1]);
 
 	ast = ch->ast;
-	if (ast && MISDN_ASTERISK_TECH_PVT(ast)) {
+	if (ast) {
+		MISDN_ASTERISK_TECH_PVT(ast) = NULL;
 		chan_misdn_log(1, bc->port,
-			"* RELEASING CHANNEL pid:%d context:%s dialed:%s caller:\"%s\" <%s> state: %s\n",
+			"* RELEASING CHANNEL pid:%d context:%s dialed:%s caller:\"%s\" <%s>\n",
 			bc->pid,
 			ast->context,
 			ast->exten,
 			ast->cid.cid_name ? ast->cid.cid_name : "",
-			ast->cid.cid_num ? ast->cid.cid_num : "",
-			misdn_get_ch_state(ch));
-		chan_misdn_log(3, bc->port, " --> * State Down\n");
-		MISDN_ASTERISK_TECH_PVT(ast) = NULL;
+			ast->cid.cid_num ? ast->cid.cid_num : "");
 
 		if (ast->_state != AST_STATE_RESERVED) {
 			chan_misdn_log(3, bc->port, " --> Setting AST State to down\n");
@@ -8112,25 +8119,118 @@ static void release_chan(struct misdn_bchannel *bc)
 		}
 	}
 
+	ast_free(ch);
+
+	ast_mutex_unlock(&release_lock);
+}
+
+/*!
+ * \internal
+ * \brief Do everything in release_chan() that makes sense without a bc.
+ *
+ * \param ch Call channel record to release.
+ *
+ * \return Nothing
+ *
+ * \note ch must not be referenced after calling.
+ */
+static void release_chan_early(struct chan_list *ch)
+{
+	struct ast_channel *ast;
+
 	ch->state = MISDN_CLEANING;
+
+	ast_mutex_lock(&release_lock);
+
+#if defined(AST_MISDN_ENHANCEMENTS)
+	if (ch->peer) {
+		ao2_ref(ch->peer, -1);
+		ch->peer = NULL;
+	}
+#endif /* AST_MISDN_ENHANCEMENTS */
+
 	cl_dequeue_chan(&cl_te, ch);
 
+	/* releasing jitterbuffer */
+	if (ch->jb) {
+		misdn_jb_destroy(ch->jb);
+		ch->jb = NULL;
+	}
+
+	if (ch->overlap_dial) {
+		if (ch->overlap_dial_task != -1) {
+			misdn_tasks_remove(ch->overlap_dial_task);
+			ch->overlap_dial_task = -1;
+		}
+		ast_mutex_destroy(&ch->overlap_tv_lock);
+	}
+
+	if (ch->hold.state != MISDN_HOLD_IDLE) {
+		if (ch->originator == ORG_AST) {
+			--misdn_out_calls[ch->hold.port];
+		} else {
+			--misdn_in_calls[ch->hold.port];
+		}
+	}
+
+	close(ch->pipe[0]);
+	close(ch->pipe[1]);
+
+	ast = ch->ast;
+	if (ast) {
+		MISDN_ASTERISK_TECH_PVT(ast) = NULL;
+		if (ast->_state != AST_STATE_RESERVED) {
+			ast_setstate(ast, AST_STATE_DOWN);
+		}
+	}
+
 	ast_free(ch);
 
 	ast_mutex_unlock(&release_lock);
 }
 
-static void misdn_transfer_bc(struct chan_list *tmp_ch, struct chan_list *holded_chan)
+/*!
+ * \internal
+ * \brief Attempt to transfer the active channel party to the held channel party.
+ *
+ * \param active_ch Channel currently connected.
+ * \param held_ch Channel currently on hold.
+ *
+ * \retval 0 on success.
+ * \retval -1 on error.
+ */
+static int misdn_attempt_transfer(struct chan_list *active_ch, struct chan_list *held_ch)
 {
-	chan_misdn_log(4, 0, "TRANSFERRING %s to %s\n", holded_chan->ast->name, tmp_ch->ast->name);
+	int retval;
+	struct ast_channel *bridged;
 
-	tmp_ch->state = MISDN_HOLD_DISCONNECT;
+	switch (active_ch->state) {
+	case MISDN_PROCEEDING:
+	case MISDN_PROGRESS:
+	case MISDN_ALERTING:
+	case MISDN_CONNECTED:
+		break;
+	default:
+		return -1;
+	}
 
-	ast_moh_stop(ast_bridged_channel(holded_chan->ast));
+	bridged = ast_bridged_channel(held_ch->ast);
+	if (bridged) {
+		ast_queue_control(held_ch->ast, AST_CONTROL_UNHOLD);
+		held_ch->hold.state = MISDN_HOLD_TRANSFER;
 
-	holded_chan->state = MISDN_CONNECTED;
-	/* misdn_lib_transfer(holded_chan->bc); */
-	ast_channel_masquerade(holded_chan->ast, ast_bridged_channel(tmp_ch->ast));
+		chan_misdn_log(1, held_ch->hold.port, "TRANSFERRING %s to %s\n",
+			held_ch->ast->name, active_ch->ast->name);
+		retval = ast_channel_masquerade(active_ch->ast, bridged);
+	} else {
+		/*
+		 * Could not transfer.  Held channel is not bridged anymore.
+		 * Held party probably got tired of waiting and hung up.
+		 */
+		retval = -1;
+	}
+
+	return retval;
 }
 
 
@@ -8169,7 +8269,7 @@ static void do_immediate_setup(struct misdn_bchannel *bc, struct chan_list *ch,
 	if (!ast_canmatch_extension(ast, ast->context, ast->exten, 1, bc->caller.number) || pbx_start_chan(ch) < 0) {
 		ast = NULL;
 		bc->out_cause = AST_CAUSE_UNALLOCATED;
-		hangup_chan(ch);
+		hangup_chan(ch, bc);
 		hanguptone_indicate(ch);
 
 		misdn_lib_send_event(bc, bc->nt ? EVENT_RELEASE_COMPLETE : EVENT_DISCONNECT);
@@ -8351,7 +8451,7 @@ int add_out_calls(int port)
 static void start_pbx(struct chan_list *ch, struct misdn_bchannel *bc, struct ast_channel *chan)
 {
 	if (pbx_start_chan(ch) < 0) {
-		hangup_chan(ch);
+		hangup_chan(ch, bc);
 		chan_misdn_log(-1, bc->port, "ast_pbx_start returned <0 in SETUP\n");
 		if (bc->nt) {
 			hanguptone_indicate(ch);
@@ -9299,6 +9399,7 @@ cb_events(enum event_e event, struct misdn_bchannel *bc, void *user_data)
 #if defined(AST_MISDN_ENHANCEMENTS)
 	struct misdn_cc_record *cc_record;
 #endif	/* defined(AST_MISDN_ENHANCEMENTS) */
+	struct chan_list *held_ch;
 	struct chan_list *ch = find_chan_by_bc(cl_te, bc);
 
 	if (event != EVENT_BCHAN_DATA && event != EVENT_TONE_GENERATE) {
@@ -9327,15 +9428,14 @@ cb_events(enum event_e event, struct misdn_bchannel *bc, void *user_data)
 		switch(event) {
 		case EVENT_SETUP:
 		case EVENT_DISCONNECT:
+		case EVENT_RELEASE:
+		case EVENT_RELEASE_COMPLETE:
 		case EVENT_PORT_ALARM:
 		case EVENT_RETRIEVE:
 		case EVENT_NEW_BC:
 		case EVENT_FACILITY:
 		case EVENT_REGISTER:
 			break;
-		case EVENT_RELEASE_COMPLETE:
-			chan_misdn_log(1, bc->port, " --> no Ch, so we've already released.\n");
-			break;
 		case EVENT_CLEANUP:
 		case EVENT_TONE_GENERATE:
 		case EVENT_BCHAN_DATA:
@@ -9396,7 +9496,7 @@ cb_events(enum event_e event, struct misdn_bchannel *bc, void *user_data)
 
 	case EVENT_NEW_BC:
 		if (!ch) {
-			ch = find_holded(cl_te,bc);
+			ch = find_hold_call(cl_te,bc);
 		}
 
 		if (!ch) {
@@ -9458,10 +9558,10 @@ cb_events(enum event_e event, struct misdn_bchannel *bc, void *user_data)
 			/* Check for Pickup Request first */
 			if (!strcmp(ch->ast->exten, ast_pickup_ext())) {
 				if (ast_pickup_call(ch->ast)) {
-					hangup_chan(ch);
+					hangup_chan(ch, bc);
 				} else {
 					ch->state = MISDN_CALLING_ACKNOWLEDGE;
-					hangup_chan(ch);
+					hangup_chan(ch, bc);
 					ch->ast = NULL;
 					break;
 				}
@@ -9681,10 +9781,10 @@ cb_events(enum event_e event, struct misdn_bchannel *bc, void *user_data)
 				ch->state = MISDN_INCOMING_SETUP;
 			}
 			if (ast_pickup_call(chan)) {
-				hangup_chan(ch);
+				hangup_chan(ch, bc);
 			} else {
 				ch->state = MISDN_CALLING_ACKNOWLEDGE;
-				hangup_chan(ch);
+				hangup_chan(ch, bc);
 				ch->ast = NULL;
 				break;
 			}
@@ -9988,8 +10088,6 @@ cb_events(enum event_e event, struct misdn_bchannel *bc, void *user_data)
 	case EVENT_DISCONNECT:
 		/* we might not have an ch->ast ptr here anymore */
 		if (ch) {
-			struct chan_list *holded_ch = find_holded(cl_te, bc);
-
 			if (bc->fac_in.Function != Fac_None) {
 				misdn_facility_ie_handler(event, bc, ch);
 			}
@@ -10016,23 +10114,40 @@ cb_events(enum event_e event, struct misdn_bchannel *bc, void *user_data)
 				break;
 			}
 
-			/* Check for holded channel, to implement transfer */
-			if (holded_ch && holded_ch != ch && ch->ast && ch->state == MISDN_CONNECTED) {
-				cb_log(1, bc->port, " --> found holded ch\n");
-				misdn_transfer_bc(ch, holded_ch) ;
-			}
-
 			bc->need_disconnect = 0;
-
 			stop_bc_tones(ch);
-			hangup_chan(ch);
-#if 0
+
+			/* Check for held channel, to implement transfer */
+			held_ch = find_hold_call(cl_te, bc);
+			if (!held_ch || !ch->ast || misdn_attempt_transfer(ch, held_ch)) {
+				hangup_chan(ch, bc);
+			}
 		} else {
-			ch = find_holded_l3(cl_te, bc->l3_id,1);
-			if (ch) {
-				hangup_chan(ch);
+			held_ch = find_hold_call_l3(cl_te, bc->l3_id);
+			if (held_ch) {
+				if (bc->fac_in.Function != Fac_None) {
+					misdn_facility_ie_handler(event, bc, held_ch);
+				}
+
+				if (held_ch->hold.state == MISDN_HOLD_ACTIVE) {
+					bc->need_disconnect = 0;
+
+#if defined(TRANSFER_ON_HELD_CALL_HANGUP)
+					/*
+					 * Some phones disconnect the held call and the active call at the
+					 * same time to do the transfer.  Unfortunately, either call could
+					 * be disconnected first.
+					 */
+					ch = find_hold_active_call(cl_te, bc);
+					if (!ch || misdn_attempt_transfer(ch, held_ch)) {
+						held_ch->hold.state = MISDN_HOLD_DISCONNECT;
+						hangup_chan(held_ch, bc);
+					}
+#else
+					hangup_chan(held_ch, bc);
+#endif	/* defined(TRANSFER_ON_HELD_CALL_HANGUP) */
+				}
 			}
-#endif
 		}
 		bc->out_cause = -1;
 		if (bc->need_release) {
@@ -10040,6 +10155,15 @@ cb_events(enum event_e event, struct misdn_bchannel *bc, void *user_data)
 		}
 		break;
 	case EVENT_RELEASE:
+		if (!ch) {
+			ch = find_hold_call_l3(cl_te, bc->l3_id);
+			if (!ch) {
+				chan_misdn_log(1, bc->port,
+					" --> no Ch, so we've already released. (%s)\n",
+					manager_isdn_get_info(event));
+				return -1;
+			}
+		}
 		if (bc->fac_in.Function != Fac_None) {
 			misdn_facility_ie_handler(event, bc, ch);
 		}
@@ -10047,12 +10171,12 @@ cb_events(enum event_e event, struct misdn_bchannel *bc, void *user_data)
 		bc->need_disconnect = 0;
 		bc->need_release = 0;
 
-		hangup_chan(ch);
-		release_chan(bc);
+		hangup_chan(ch, bc);
+		release_chan(ch, bc);
 		break;
 	case EVENT_RELEASE_COMPLETE:
-		if (bc->fac_in.Function != Fac_None) {
-			misdn_facility_ie_handler(event, bc, ch);
+		if (!ch) {
+			ch = find_hold_call_l3(cl_te, bc->l3_id);
 		}
 
 		bc->need_disconnect = 0;
@@ -10060,11 +10184,15 @@ cb_events(enum event_e event, struct misdn_bchannel *bc, void *user_data)
 		bc->need_release_complete = 0;
 
 		if (ch) {
+			if (bc->fac_in.Function != Fac_None) {
+				misdn_facility_ie_handler(event, bc, ch);
+			}
+
 			stop_bc_tones(ch);
-			hangup_chan(ch);
-			ch->state = MISDN_CLEANING;
-#if defined(AST_MISDN_ENHANCEMENTS)
+			hangup_chan(ch, bc);
+			release_chan(ch, bc);
 		} else {
+#if defined(AST_MISDN_ENHANCEMENTS)
 			/*
 			 * A call-completion signaling link established with
 			 * REGISTER does not have a struct chan_list record
@@ -10078,9 +10206,11 @@ cb_events(enum event_e event, struct misdn_bchannel *bc, void *user_data)
 			}
 			AST_LIST_UNLOCK(&misdn_cc_records_db);
 #endif	/* defined(AST_MISDN_ENHANCEMENTS) */
-		}
 
-		release_chan(bc);
+			chan_misdn_log(1, bc->port,
+				" --> no Ch, so we've already released. (%s)\n",
+				manager_isdn_get_info(event));
+		}
 		break;
 	case EVENT_BCHAN_ERROR:
 	case EVENT_CLEANUP:
@@ -10094,8 +10224,8 @@ cb_events(enum event_e event, struct misdn_bchannel *bc, void *user_data)
 			break;
 		}
 
-		hangup_chan(ch);
-		release_chan(bc);
+		hangup_chan(ch, bc);
+		release_chan(ch, bc);
 		break;
 	case EVENT_TONE_GENERATE:
 	{
@@ -10181,8 +10311,8 @@ cb_events(enum event_e event, struct misdn_bchannel *bc, void *user_data)
 					chan_misdn_log(0, bc->port, "Write returned <=0 (err=%s) --> hanging up channel\n", strerror(errno));
 
 					stop_bc_tones(ch);
-					hangup_chan(ch);
-					release_chan(bc);
+					hangup_chan(ch, bc);
+					release_chan(ch, bc);
 				}
 			} else {
 				chan_misdn_log(1, bc->port, "Write Pipe full!\n");
@@ -10237,67 +10367,56 @@ cb_events(enum event_e event, struct misdn_bchannel *bc, void *user_data)
 	/** Supplementary Services **/
 	/****************************/
 	case EVENT_RETRIEVE:
-	{
-		struct ast_channel *hold_ast;
-
-		if (!ch) {
-			chan_misdn_log(4, bc->port, " --> no CH, searching in holded\n");
-			ch = find_holded_l3(cl_te, bc->l3_id, 1);
-		}
-
 		if (!ch) {
-			ast_log(LOG_WARNING, "Found no Holded channel, cannot Retrieve\n");
-			misdn_lib_send_event(bc, EVENT_RETRIEVE_REJECT);
-			break;
+			chan_misdn_log(4, bc->port, " --> no CH, searching for held call\n");
+			ch = find_hold_call_l3(cl_te, bc->l3_id);
+			if (!ch || ch->hold.state != MISDN_HOLD_ACTIVE) {
+				ast_log(LOG_WARNING, "No held call found, cannot Retrieve\n");
+				misdn_lib_send_event(bc, EVENT_RETRIEVE_REJECT);
+				break;
+			}
 		}
 
-		/*remember the channel again*/
+		/* remember the channel again */
 		ch->bc = bc;
-		ch->state = MISDN_CONNECTED;
-
-		ch->hold_info.port = 0;
-		ch->hold_info.channel = 0;
 
-		hold_ast = ast_bridged_channel(ch->ast);
+		ch->hold.state = MISDN_HOLD_IDLE;
+		ch->hold.port = 0;
+		ch->hold.channel = 0;
 
-		if (hold_ast) {
-			ast_moh_stop(hold_ast);
-		}
+		ast_queue_control(ch->ast, AST_CONTROL_UNHOLD);
 
 		if (misdn_lib_send_event(bc, EVENT_RETRIEVE_ACKNOWLEDGE) < 0) {
 			chan_misdn_log(4, bc->port, " --> RETRIEVE_ACK failed\n");
 			misdn_lib_send_event(bc, EVENT_RETRIEVE_REJECT);
 		}
 		break;
-	}
 	case EVENT_HOLD:
 	{
 		int hold_allowed;
-		struct ast_channel *bridged = ast_bridged_channel(ch->ast);
+		struct ast_channel *bridged;
 
 		misdn_cfg_get(bc->port, MISDN_CFG_HOLD_ALLOWED, &hold_allowed, sizeof(hold_allowed));
-
 		if (!hold_allowed) {
 			chan_misdn_log(-1, bc->port, "Hold not allowed this port.\n");
 			misdn_lib_send_event(bc, EVENT_HOLD_REJECT);
 			break;
 		}
 
+		bridged = ast_bridged_channel(ch->ast);
 		if (bridged) {
 			chan_misdn_log(2, bc->port, "Bridge Partner is of type: %s\n", bridged->tech->type);
-			ch->state = MISDN_HOLDED;
 			ch->l3id = bc->l3_id;
 
-			misdn_lib_send_event(bc, EVENT_HOLD_ACKNOWLEDGE);
+			/* forget the channel now */
+			ch->bc = NULL;
+			ch->hold.state = MISDN_HOLD_ACTIVE;
+			ch->hold.port = bc->port;
+			ch->hold.channel = bc->channel;
 
-			/* XXX This should queue an AST_CONTROL_HOLD frame on this channel
-			 * instead of starting moh on the bridged channel directly */
-			ast_moh_start(bridged, NULL, NULL);
+			ast_queue_control(ch->ast, AST_CONTROL_HOLD);
 
-			/*forget the channel now*/
-			ch->bc = NULL;
-			ch->hold_info.port = bc->port;
-			ch->hold_info.channel = bc->channel;
+			misdn_lib_send_event(bc, EVENT_HOLD_ACKNOWLEDGE);
 		} else {
 			misdn_lib_send_event(bc, EVENT_HOLD_REJECT);
 			chan_misdn_log(0, bc->port, "We aren't bridged to anybody\n");
@@ -10379,7 +10498,7 @@ cb_events(enum event_e event, struct misdn_bchannel *bc, void *user_data)
 	case EVENT_RESTART:
 		if (!bc->dummy) {
 			stop_bc_tones(ch);
-			release_chan(bc);
+			release_chan(ch, bc);
 		}
 		break;
 	default:
diff --git a/channels/misdn/isdn_lib.c b/channels/misdn/isdn_lib.c
index 10590d64f..8cd2fd10f 100644
--- a/channels/misdn/isdn_lib.c
+++ b/channels/misdn/isdn_lib.c
@@ -240,8 +240,6 @@ struct misdn_bchannel *find_bc_by_l3id(struct misdn_stack *stack, unsigned long
 
 struct misdn_bchannel *find_bc_by_confid(unsigned long confid);
 
-struct misdn_bchannel *stack_holder_find_bychan(struct misdn_stack *stack, int chan);
-
 int setup_bc(struct misdn_bchannel *bc);
 
 int manager_isdn_handler(iframe_t *frm ,msg_t *msg);
@@ -3208,13 +3206,6 @@ void te_lib_destroy(int midev)
 	cb_log(4, 0, "midev closed\n");
 }
 
-
-
-void misdn_lib_transfer(struct misdn_bchannel* holded_bc)
-{
-	holded_bc->holded=0;
-}
-
 struct misdn_bchannel *manager_find_bc_by_pid(int pid)
 {
 	struct misdn_stack *stack;
@@ -3594,7 +3585,7 @@ int misdn_lib_send_event(struct misdn_bchannel *bc, enum event_e event )
 {
 	msg_t *msg;
 	struct misdn_bchannel *bc2;
-	struct misdn_bchannel *holded_bc;
+	struct misdn_bchannel *held_bc;
 	struct misdn_stack *stack;
 	int retval = 0;
 	int channel;
@@ -3705,20 +3696,22 @@ int misdn_lib_send_event(struct misdn_bchannel *bc, enum event_e event )
 		break;
 
 	case EVENT_HOLD_ACKNOWLEDGE:
-		holded_bc = malloc(sizeof(struct misdn_bchannel));
-		if (!holded_bc) {
-			cb_log(0,bc->port, "Could not allocate holded_bc!!!\n");
+		held_bc = malloc(sizeof(struct misdn_bchannel));
+		if (!held_bc) {
+			cb_log(0, bc->port, "Could not allocate held_bc!!!\n");
 			RETURN(-1,OUT);
 		}
 
-		/*backup the bc*/
-		memcpy(holded_bc,bc,sizeof(struct misdn_bchannel));
-		holded_bc->holded=1;
-		bc_state_change(holded_bc,BCHAN_CLEANED);
-
-		stack_holder_add(stack,holded_bc);
+		/* backup the bc and put it in storage */
+		*held_bc = *bc;
+		held_bc->holded = 1;
+		held_bc->channel = 0;/* A held call does not have a channel anymore. */
+		held_bc->channel_preselected = 0;
+		held_bc->channel_found = 0;
+		bc_state_change(held_bc, BCHAN_CLEANED);
+		stack_holder_add(stack, held_bc);
 
-		/*kill the bridge and clean the bchannel*/
+		/* kill the bridge and clean the real b-channel record */
 		if (stack->nt) {
 			if (bc->bc_state == BCHAN_BRIDGED) {
 				misdn_split_conf(bc,bc->conf_id);
@@ -4681,28 +4674,6 @@ void stack_holder_remove(struct misdn_stack *stack, struct misdn_bchannel *holde
 	}
 }
 
-struct misdn_bchannel *stack_holder_find_bychan(struct misdn_stack *stack, int chan)
-{
-	struct misdn_bchannel *help;
-
-	cb_log(4,stack?stack->port:0, "*HOLDER: find_bychan %c\n", chan);
-
-	if (!stack) return NULL;
-
-	for (help=stack->holding;
-	     help;
-	     help=help->next) {
-		if (help->channel == chan) {
-			cb_log(4,stack->port, "*HOLDER: found_bychan bc\n");
-			return help;
-		}
-	}
-
-	cb_log(4,stack->port, "*HOLDER: find_bychan nothing\n");
-	return NULL;
-
-}
-
 struct misdn_bchannel *stack_holder_find(struct misdn_stack *stack, unsigned long l3id)
 {
 	struct misdn_bchannel *help;
@@ -4724,7 +4695,29 @@ struct misdn_bchannel *stack_holder_find(struct misdn_stack *stack, unsigned lon
 	return NULL;
 }
 
+/*!
+ * \brief Find a held call's B channel record.
+ *
+ * \param port Port the call is on.
+ * \param l3_id mISDN Layer 3 ID of held call.
+ *
+ * \return Found bc-record or NULL.
+ */
+struct misdn_bchannel *misdn_lib_find_held_bc(int port, int l3_id)
+{
+	struct misdn_bchannel *bc;
+	struct misdn_stack *stack;
+
+	bc = NULL;
+	for (stack = get_misdn_stack(); stack; stack = stack->next) {
+		if (stack->port == port) {
+			bc = stack_holder_find(stack, l3_id);
+			break;
+		}
+	}
 
+	return bc;
+}
 
 void misdn_lib_send_tone(struct misdn_bchannel *bc, enum tone_e tone)
 {
diff --git a/channels/misdn/isdn_lib.h b/channels/misdn/isdn_lib.h
index 934be9830..89565327e 100644
--- a/channels/misdn/isdn_lib.h
+++ b/channels/misdn/isdn_lib.h
@@ -753,8 +753,6 @@ void misdn_lib_log_ies(struct misdn_bchannel *bc);
 
 char *manager_isdn_get_info(enum event_e event);
 
-void misdn_lib_transfer(struct misdn_bchannel* holded_bc);
-
 struct misdn_bchannel* misdn_lib_get_free_bc(int port, int channel, int inout, int dec);
 #if defined(AST_MISDN_ENHANCEMENTS)
 struct misdn_bchannel *misdn_lib_get_register_bc(int port);
@@ -793,6 +791,7 @@ int misdn_lib_get_port_up (int port) ;
 
 int misdn_lib_maxports_get(void) ;
 
+struct misdn_bchannel *misdn_lib_find_held_bc(int port, int l3_id);
 void misdn_lib_release(struct misdn_bchannel *bc);
 
 int misdn_cap_is_speech(int cap);