From f9c3c8d02616fb151b900b85df624f6a10edda92 Mon Sep 17 00:00:00 2001
From: Richard Mudgett <rmudgett@digium.com>
Date: Thu, 21 Oct 2010 17:30:41 +0000
Subject: [PATCH] Extract the layer 2 link structure out of struct pri.

This completes the layer 2 link and Q.931 call control restructuring.
Some code is now simplified since there is only one D channel control
structure and the amount of allocated memory is reduced.


git-svn-id: https://origsvn.digium.com/svn/libpri/branches/1.4@2077 2fbb986a-6c06-0410-b554-c9c1f0a7f128
---
 pri.c          | 305 ++++++++++++++++++++------------
 pri_aoc.c      |  15 +-
 pri_cc.c       |  51 ++----
 pri_facility.c |  27 ++-
 pri_internal.h | 115 +++---------
 pri_q921.h     |  66 ++++++-
 pri_q931.h     |   4 +-
 prisched.c     |  15 --
 q921.c         | 472 +++++++++++++++++++++++++------------------------
 q931.c         | 107 +++++------
 10 files changed, 600 insertions(+), 577 deletions(-)

diff --git a/pri.c b/pri.c
index 36ee69c..d5ac4c5 100644
--- a/pri.c
+++ b/pri.c
@@ -225,7 +225,6 @@ int pri_set_timer(struct pri *ctrl, int timer, int value)
 	if (!ctrl || timer < 0 || PRI_MAX_TIMERS <= timer || value < 0) {
 		return -1;
 	}
-	ctrl = PRI_MASTER(ctrl);
 	ctrl->timers[timer] = value;
 	return 0;
 }
@@ -235,7 +234,6 @@ int pri_get_timer(struct pri *ctrl, int timer)
 	if (!ctrl || timer < 0 || PRI_MAX_TIMERS <= timer) {
 		return -1;
 	}
-	ctrl = PRI_MASTER(ctrl);
 	return ctrl->timers[timer];
 }
 
@@ -285,34 +283,150 @@ static int __pri_write(struct pri *pri, void *buf, int buflen)
 	return res;
 }
 
-void __pri_free_tei(struct pri * p)
+/*!
+ * \brief Destroy the given link.
+ *
+ * \param link Q.921 link to destroy.
+ *
+ * \return Nothing
+ */
+void pri_link_destroy(struct q921_link *link)
+{
+	if (link) {
+		struct q931_call *call;
+
+		call = link->dummy_call;
+		if (call) {
+			pri_schedule_del(call->pri, call->retranstimer);
+			call->retranstimer = 0;
+			pri_call_apdu_queue_cleanup(call);
+		}
+		free(link);
+	}
+}
+
+/*!
+ * \internal
+ * \brief Initialize the layer 2 link structure.
+ *
+ * \param ctrl D channel controller.
+ * \param link Q.921 link to initialize.
+ * \param sapi SAPI new link is to use.
+ * \param tei TEI new link is to use.
+ *
+ * \note It is assumed that the link has already been memset to zero.
+ *
+ * \return Nothing
+ */
+static void pri_link_init(struct pri *ctrl, struct q921_link *link, int sapi, int tei)
+{
+	link->ctrl = ctrl;
+	link->sapi = sapi;
+	link->tei = tei;
+}
+
+/*!
+ * \brief Create a new layer 2 link.
+ *
+ * \param ctrl D channel controller.
+ * \param sapi SAPI new link is to use.
+ * \param tei TEI new link is to use.
+ *
+ * \retval link on success.
+ * \retval NULL on error.
+ */
+struct q921_link *pri_link_new(struct pri *ctrl, int sapi, int tei)
+{
+	struct link_dummy *dummy_link;
+	struct q921_link *link;
+
+	switch (ctrl->switchtype) {
+	case PRI_SWITCH_GR303_EOC:
+	case PRI_SWITCH_GR303_TMC:
+		link = calloc(1, sizeof(*link));
+		if (!link) {
+			return NULL;
+		}
+		dummy_link = NULL;
+		break;
+	default:
+		dummy_link = calloc(1, sizeof(*dummy_link));
+		if (!dummy_link) {
+			return NULL;
+		}
+		link = &dummy_link->link;
+		break;
+	}
+
+	pri_link_init(ctrl, link, sapi, tei);
+	if (dummy_link) {
+		/* Initialize the dummy call reference call record. */
+		link->dummy_call = &dummy_link->dummy_call;
+		q931_init_call_record(link, link->dummy_call, Q931_DUMMY_CALL_REFERENCE);
+	}
+
+	q921_start(link);
+
+	return link;
+}
+
+/*!
+ * \internal
+ * \brief Destroy the given D channel controller.
+ *
+ * \param ctrl D channel control to destroy.
+ *
+ * \return Nothing
+ */
+static void pri_ctrl_destroy(struct pri *ctrl)
 {
-	if (p) {
+	if (ctrl) {
 		struct q931_call *call;
 
-		call = p->dummy_call;
+		if (ctrl->link.tei == Q921_TEI_GROUP
+			&& ctrl->link.sapi == Q921_SAPI_LAYER2_MANAGEMENT
+			&& ctrl->localtype == PRI_CPE) {
+			/* This dummy call was borrowed from the specific TEI link. */
+			call = NULL;
+		} else {
+			call = ctrl->link.dummy_call;
+		}
 		if (call) {
 			pri_schedule_del(call->pri, call->retranstimer);
 			call->retranstimer = 0;
 			pri_call_apdu_queue_cleanup(call);
 		}
-		free(p->msg_line);
-		free(p->sched.timer);
-		free(p);
+		free(ctrl->msg_line);
+		free(ctrl->sched.timer);
+		free(ctrl);
 	}
 }
 
-struct pri *__pri_new_tei(int fd, int node, int switchtype, struct pri *master, pri_io_cb rd, pri_io_cb wr, void *userdata, int tei, int bri)
+/*!
+ * \internal
+ * \brief Create a new D channel control structure.
+ *
+ * \param fd D channel file descriptor if no callback functions supplied.
+ * \param node Switch NET/CPE type
+ * \param switchtype ISDN switch type
+ * \param rd D channel read callback function
+ * \param wr D channel write callback function
+ * \param userdata Callback function parameter
+ * \param tei TEI new link is to use.
+ * \param bri TRUE if interface is BRI
+ *
+ * \retval ctrl on success.
+ * \retval NULL on error.
+ */
+static struct pri *pri_ctrl_new(int fd, int node, int switchtype, pri_io_cb rd, pri_io_cb wr, void *userdata, int tei, int bri)
 {
 	int create_dummy_call;
 	struct d_ctrl_dummy *dummy_ctrl;
-	struct pri *p;
+	struct pri *ctrl;
 
 	switch (switchtype) {
 	case PRI_SWITCH_GR303_EOC:
 	case PRI_SWITCH_GR303_TMC:
-	case PRI_SWITCH_GR303_TMC_SWITCHING:
-	case PRI_SWITCH_GR303_EOC_PATH:
 		create_dummy_call = 0;
 		break;
 	default:
@@ -332,96 +446,75 @@ struct pri *__pri_new_tei(int fd, int node, int switchtype, struct pri *master,
 		if (!dummy_ctrl) {
 			return NULL;
 		}
-		p = &dummy_ctrl->ctrl;
+		ctrl = &dummy_ctrl->ctrl;
 	} else {
-		p = calloc(1, sizeof(*p));
-		if (!p) {
+		ctrl = calloc(1, sizeof(*ctrl));
+		if (!ctrl) {
 			return NULL;
 		}
 		dummy_ctrl = NULL;
 	}
-	if (!master) {
-		/* This is the master record. */
-		p->msg_line = calloc(1, sizeof(*p->msg_line));
-		if (!p->msg_line) {
-			free(p);
-			return NULL;
-		}
+	ctrl->msg_line = calloc(1, sizeof(*ctrl->msg_line));
+	if (!ctrl->msg_line) {
+		free(ctrl);
+		return NULL;
 	}
 
-	p->bri = bri;
-	p->fd = fd;
-	p->read_func = rd;
-	p->write_func = wr;
-	p->userdata = userdata;
-	p->localtype = node;
-	p->switchtype = switchtype;
-	p->cref = 1;
-	p->sapi = (tei == Q921_TEI_GROUP) ? Q921_SAPI_LAYER2_MANAGEMENT : Q921_SAPI_CALL_CTRL;
-	p->tei = tei;
-	p->nsf = PRI_NSF_NONE;
-	p->protodisc = Q931_PROTOCOL_DISCRIMINATOR;
-	p->master = master;
-	p->callpool = &p->localpool;
-	pri_default_timers(p, switchtype);
-	if (master) {
-		pri_set_debug(p, master->debug);
-		pri_set_inbanddisconnect(p, master->acceptinbanddisconnect);
-		if (master->sendfacility)
-			pri_facility_enable(p);
-	}
+	ctrl->bri = bri;
+	ctrl->fd = fd;
+	ctrl->read_func = rd;
+	ctrl->write_func = wr;
+	ctrl->userdata = userdata;
+	ctrl->localtype = node;
+	ctrl->switchtype = switchtype;
+	ctrl->cref = 1;
+	ctrl->nsf = PRI_NSF_NONE;
+	ctrl->callpool = &ctrl->localpool;
+	pri_default_timers(ctrl, switchtype);
 #ifdef LIBPRI_COUNTERS
-	p->q921_rxcount = 0;
-	p->q921_txcount = 0;
-	p->q931_rxcount = 0;
-	p->q931_txcount = 0;
+	ctrl->q921_rxcount = 0;
+	ctrl->q921_txcount = 0;
+	ctrl->q931_rxcount = 0;
+	ctrl->q931_txcount = 0;
 #endif
-	if (dummy_ctrl) {
-		/* Initialize the dummy call reference call record. */
-		dummy_ctrl->ctrl.dummy_call = &dummy_ctrl->dummy_call;
-		q931_init_call_record(&dummy_ctrl->ctrl, dummy_ctrl->ctrl.dummy_call,
-			Q931_DUMMY_CALL_REFERENCE);
-	}
 	switch (switchtype) {
 	case PRI_SWITCH_GR303_EOC:
-		p->protodisc = GR303_PROTOCOL_DISCRIMINATOR;
-		p->sapi = Q921_SAPI_GR303_EOC;
-		p->tei = Q921_TEI_GR303_EOC_OPS;
-		p->subchannel = __pri_new_tei(-1, node, PRI_SWITCH_GR303_EOC_PATH, p, NULL, NULL, NULL, Q921_TEI_GR303_EOC_PATH, 0);
-		if (!p->subchannel) {
-			free(p);
+		ctrl->protodisc = GR303_PROTOCOL_DISCRIMINATOR;
+		pri_link_init(ctrl, &ctrl->link, Q921_SAPI_GR303_EOC, Q921_TEI_GR303_EOC_OPS);
+		ctrl->link.next = pri_link_new(ctrl, Q921_SAPI_GR303_EOC, Q921_TEI_GR303_EOC_PATH);
+		if (!ctrl->link.next) {
+			pri_ctrl_destroy(ctrl);
 			return NULL;
 		}
 		break;
 	case PRI_SWITCH_GR303_TMC:
-		p->protodisc = GR303_PROTOCOL_DISCRIMINATOR;
-		p->sapi = Q921_SAPI_GR303_TMC_CALLPROC;
-		p->tei = Q921_TEI_GR303_TMC_CALLPROC;
-		p->subchannel = __pri_new_tei(-1, node, PRI_SWITCH_GR303_TMC_SWITCHING, p, NULL, NULL, NULL, Q921_TEI_GR303_TMC_SWITCHING, 0);
-		if (!p->subchannel) {
-			free(p);
+		ctrl->protodisc = GR303_PROTOCOL_DISCRIMINATOR;
+		pri_link_init(ctrl, &ctrl->link, Q921_SAPI_GR303_TMC_CALLPROC, Q921_TEI_GR303_TMC_CALLPROC);
+		ctrl->link.next = pri_link_new(ctrl, Q921_SAPI_GR303_TMC_SWITCHING, Q921_TEI_GR303_TMC_SWITCHING);
+		if (!ctrl->link.next) {
+			pri_ctrl_destroy(ctrl);
 			return NULL;
 		}
 		break;
-	case PRI_SWITCH_GR303_TMC_SWITCHING:
-		p->protodisc = GR303_PROTOCOL_DISCRIMINATOR;
-		p->sapi = Q921_SAPI_GR303_TMC_SWITCHING;
-		p->tei = Q921_TEI_GR303_TMC_SWITCHING;
-		break;
-	case PRI_SWITCH_GR303_EOC_PATH:
-		p->protodisc = GR303_PROTOCOL_DISCRIMINATOR;
-		p->sapi = Q921_SAPI_GR303_EOC;
-		p->tei = Q921_TEI_GR303_EOC_PATH;
-		break;
 	default:
+		ctrl->protodisc = Q931_PROTOCOL_DISCRIMINATOR;
+		pri_link_init(ctrl, &ctrl->link,
+			(tei == Q921_TEI_GROUP) ? Q921_SAPI_LAYER2_MANAGEMENT : Q921_SAPI_CALL_CTRL,
+			tei);
 		break;
 	}
+	if (dummy_ctrl) {
+		/* Initialize the dummy call reference call record. */
+		ctrl->link.dummy_call = &dummy_ctrl->dummy_call;
+		q931_init_call_record(&ctrl->link, ctrl->link.dummy_call,
+			Q931_DUMMY_CALL_REFERENCE);
+	}
 
-	if (p->tei == Q921_TEI_GROUP && p->sapi == Q921_SAPI_LAYER2_MANAGEMENT
-		&& p->localtype == PRI_CPE) {
-		p->subchannel = __pri_new_tei(-1, p->localtype, p->switchtype, p, NULL, NULL, NULL, Q921_TEI_PRI, 1);
-		if (!p->subchannel) {
-			free(p);
+	if (ctrl->link.tei == Q921_TEI_GROUP && ctrl->link.sapi == Q921_SAPI_LAYER2_MANAGEMENT
+		&& ctrl->localtype == PRI_CPE) {
+		ctrl->link.next = pri_link_new(ctrl, Q921_SAPI_CALL_CTRL, Q921_TEI_PRI);
+		if (!ctrl->link.next) {
+			pri_ctrl_destroy(ctrl);
 			return NULL;
 		}
 		/*
@@ -430,11 +523,12 @@ struct pri *__pri_new_tei(int fd, int node, int switchtype, struct pri *master,
 		 * to broadcast messages on the dummy call or to broadcast any
 		 * messages for that matter.
 		 */
-		p->dummy_call = p->subchannel->dummy_call;
-	} else
-		q921_start(p);
-	
-	return p;
+		ctrl->link.dummy_call = ctrl->link.next->dummy_call;
+	} else {
+		q921_start(&ctrl->link);
+	}
+
+	return ctrl;
 }
 
 void pri_call_set_useruser(q931_call *c, const char *userchars)
@@ -470,15 +564,15 @@ int pri_restart(struct pri *pri)
 
 struct pri *pri_new(int fd, int nodetype, int switchtype)
 {
-	return __pri_new_tei(fd, nodetype, switchtype, NULL, __pri_read, __pri_write, NULL, Q921_TEI_PRI, 0);
+	return pri_ctrl_new(fd, nodetype, switchtype, __pri_read, __pri_write, NULL, Q921_TEI_PRI, 0);
 }
 
 struct pri *pri_new_bri(int fd, int ptpmode, int nodetype, int switchtype)
 {
 	if (ptpmode)
-		return __pri_new_tei(fd, nodetype, switchtype, NULL, __pri_read, __pri_write, NULL, Q921_TEI_PRI, 1);
+		return pri_ctrl_new(fd, nodetype, switchtype, __pri_read, __pri_write, NULL, Q921_TEI_PRI, 1);
 	else
-		return __pri_new_tei(fd, nodetype, switchtype, NULL, __pri_read, __pri_write, NULL, Q921_TEI_GROUP, 1);
+		return pri_ctrl_new(fd, nodetype, switchtype, __pri_read, __pri_write, NULL, Q921_TEI_GROUP, 1);
 }
 
 struct pri *pri_new_cb(int fd, int nodetype, int switchtype, pri_io_cb io_read, pri_io_cb io_write, void *userdata)
@@ -487,7 +581,7 @@ struct pri *pri_new_cb(int fd, int nodetype, int switchtype, pri_io_cb io_read,
 		io_read = __pri_read;
 	if (!io_write)
 		io_write = __pri_write;
-	return __pri_new_tei(fd, nodetype, switchtype, NULL, io_read, io_write, userdata, Q921_TEI_PRI, 0);
+	return pri_ctrl_new(fd, nodetype, switchtype, io_read, io_write, userdata, Q921_TEI_PRI, 0);
 }
 
 struct pri *pri_new_bri_cb(int fd, int ptpmode, int nodetype, int switchtype, pri_io_cb io_read, pri_io_cb io_write, void *userdata)
@@ -499,9 +593,9 @@ struct pri *pri_new_bri_cb(int fd, int ptpmode, int nodetype, int switchtype, pr
 		io_write = __pri_write;
 	}
 	if (ptpmode) {
-		return __pri_new_tei(fd, nodetype, switchtype, NULL, io_read, io_write, userdata, Q921_TEI_PRI, 1);
+		return pri_ctrl_new(fd, nodetype, switchtype, io_read, io_write, userdata, Q921_TEI_PRI, 1);
 	} else {
-		return __pri_new_tei(fd, nodetype, switchtype, NULL, io_read, io_write, userdata, Q921_TEI_GROUP, 1);
+		return pri_ctrl_new(fd, nodetype, switchtype, io_read, io_write, userdata, Q921_TEI_GROUP, 1);
 	}
 }
 
@@ -647,16 +741,12 @@ void pri_set_debug(struct pri *pri, int debug)
 	if (!pri)
 		return;
 	pri->debug = debug;
-	if (pri->subchannel)
-		pri_set_debug(pri->subchannel, debug);
 }
 
 int pri_get_debug(struct pri *pri)
 {
 	if (!pri)
 		return -1;
-	if (pri->subchannel)
-		return pri_get_debug(pri->subchannel);
 	return pri->debug;
 }
 
@@ -665,9 +755,6 @@ void pri_facility_enable(struct pri *pri)
 	if (!pri)
 		return;
 	pri->sendfacility = 1;
-	if (pri->subchannel)
-		pri_facility_enable(pri->subchannel);
-	return;
 }
 
 int pri_acknowledge(struct pri *pri, q931_call *call, int channel, int info)
@@ -763,7 +850,6 @@ int pri_connect_ack(struct pri *ctrl, q931_call *call, int channel)
 void pri_connect_ack_enable(struct pri *ctrl, int enable)
 {
 	if (ctrl) {
-		ctrl = PRI_MASTER(ctrl);
 		ctrl->manual_connect_ack = enable ? 1 : 0;
 	}
 }
@@ -1162,7 +1248,6 @@ int pri_channel_bridge(q931_call *call1, q931_call *call2)
 void pri_hangup_fix_enable(struct pri *ctrl, int enable)
 {
 	if (ctrl) {
-		ctrl = PRI_MASTER(ctrl);
 		ctrl->hangup_fix_enabled = enable ? 1 : 0;
 	}
 }
@@ -1348,9 +1433,6 @@ void pri_message(struct pri *ctrl, const char *fmt, ...)
 	int added_length;
 	va_list ap;
 
-	if (ctrl) {
-		ctrl = PRI_MASTER(ctrl);
-	}
 	if (!ctrl || !ctrl->msg_line) {
 		/* Just have to do it the old way. */
 		va_start(ap, fmt);
@@ -1412,7 +1494,7 @@ void pri_error(struct pri *pri, const char *fmt, ...)
 	vsnprintf(tmp, sizeof(tmp), fmt, ap);
 	va_end(ap);
 	if (__pri_error)
-		__pri_error(pri ? PRI_MASTER(pri) : NULL, tmp);
+		__pri_error(pri, tmp);
 	else
 		fputs(tmp, stderr);
 }
@@ -1478,7 +1560,7 @@ char *pri_dump_info_str(struct pri *ctrl)
 	size_t used;
 #ifdef LIBPRI_COUNTERS
 	struct q921_frame *f;
-	struct pri *link;
+	struct q921_link *link;
 	unsigned q921outstanding;
 #endif
 	unsigned idx;
@@ -1494,8 +1576,6 @@ char *pri_dump_info_str(struct pri *ctrl)
 		return NULL;
 	}
 
-	ctrl = PRI_MASTER(ctrl);
-
 	/* Might be nice to format these a little better */
 	used = 0;
 	used = pri_snprintf(buf, used, buf_size, "Switchtype: %s\n",
@@ -1507,9 +1587,9 @@ char *pri_dump_info_str(struct pri *ctrl)
 	used = pri_snprintf(buf, used, buf_size, "Q931 TX: %d\n", ctrl->q931_txcount);
 	used = pri_snprintf(buf, used, buf_size, "Q921 RX: %d\n", ctrl->q921_rxcount);
 	used = pri_snprintf(buf, used, buf_size, "Q921 TX: %d\n", ctrl->q921_txcount);
-	for (link = ctrl; link; link = link->subchannel) {
+	for (link = &ctrl->link; link; link = link->next) {
 		q921outstanding = 0;
-		for (f = link->txqueue; f; f = f->next) {
+		for (f = link->tx_queue; f; f = f->next) {
 			++q921outstanding;
 		}
 		used = pri_snprintf(buf, used, buf_size, "Q921 Outstanding: %u (TEI=%d)\n",
@@ -1702,7 +1782,6 @@ void pri_sr_set_keypad_digits(struct pri_sr *sr, const char *keypad_digits)
 void pri_transfer_enable(struct pri *ctrl, int enable)
 {
 	if (ctrl) {
-		ctrl = PRI_MASTER(ctrl);
 		ctrl->transfer_support = enable ? 1 : 0;
 	}
 }
@@ -1710,7 +1789,6 @@ void pri_transfer_enable(struct pri *ctrl, int enable)
 void pri_hold_enable(struct pri *ctrl, int enable)
 {
 	if (ctrl) {
-		ctrl = PRI_MASTER(ctrl);
 		ctrl->hold_support = enable ? 1 : 0;
 	}
 }
@@ -1775,7 +1853,6 @@ int pri_callrerouting_facility(struct pri *pri, q931_call *call, const char *des
 void pri_reroute_enable(struct pri *ctrl, int enable)
 {
 	if (ctrl) {
-		ctrl = PRI_MASTER(ctrl);
 		ctrl->deflection_support = enable ? 1 : 0;
 	}
 }
@@ -1827,7 +1904,6 @@ int pri_reroute_call(struct pri *ctrl, q931_call *call, const struct pri_party_i
 void pri_cc_enable(struct pri *ctrl, int enable)
 {
 	if (ctrl) {
-		ctrl = PRI_MASTER(ctrl);
 		ctrl->cc_support = enable ? 1 : 0;
 	}
 }
@@ -1835,7 +1911,6 @@ void pri_cc_enable(struct pri *ctrl, int enable)
 void pri_cc_recall_mode(struct pri *ctrl, int mode)
 {
 	if (ctrl) {
-		ctrl = PRI_MASTER(ctrl);
 		ctrl->cc.option.recall_mode = mode ? 1 : 0;
 	}
 }
@@ -1843,7 +1918,6 @@ void pri_cc_recall_mode(struct pri *ctrl, int mode)
 void pri_cc_retain_signaling_req(struct pri *ctrl, int signaling_retention)
 {
 	if (ctrl && 0 <= signaling_retention && signaling_retention < 3) {
-		ctrl = PRI_MASTER(ctrl);
 		ctrl->cc.option.signaling_retention_req = signaling_retention;
 	}
 }
@@ -1851,7 +1925,6 @@ void pri_cc_retain_signaling_req(struct pri *ctrl, int signaling_retention)
 void pri_cc_retain_signaling_rsp(struct pri *ctrl, int signaling_retention)
 {
 	if (ctrl) {
-		ctrl = PRI_MASTER(ctrl);
 		ctrl->cc.option.signaling_retention_rsp = signaling_retention ? 1 : 0;
 	}
 }
diff --git a/pri_aoc.c b/pri_aoc.c
index 23d7be6..8b385e5 100644
--- a/pri_aoc.c
+++ b/pri_aoc.c
@@ -212,7 +212,7 @@ void aoc_etsi_aoc_request(struct pri *ctrl, q931_call *call, const struct rose_m
 	struct pri_subcommand *subcmd;
 	int request;
 
-	if (!PRI_MASTER(ctrl)->aoc_support) {
+	if (!ctrl->aoc_support) {
 		send_facility_error(ctrl, call, invoke->invoke_id, ROSE_ERROR_Gen_NotSubscribed);
 		return;
 	}
@@ -439,7 +439,7 @@ void aoc_etsi_aoc_s_currency(struct pri *ctrl, const struct rose_msg_invoke *inv
 {
 	struct pri_subcommand *subcmd;
 
-	if (!PRI_MASTER(ctrl)->aoc_support) {
+	if (!ctrl->aoc_support) {
 		return;
 	}
 	subcmd = q931_alloc_subcommand(ctrl);
@@ -470,7 +470,7 @@ void aoc_etsi_aoc_s_special_arrangement(struct pri *ctrl, const struct rose_msg_
 {
 	struct pri_subcommand *subcmd;
 
-	if (!PRI_MASTER(ctrl)->aoc_support) {
+	if (!ctrl->aoc_support) {
 		return;
 	}
 	subcmd = q931_alloc_subcommand(ctrl);
@@ -535,7 +535,7 @@ void aoc_etsi_aoc_d_currency(struct pri *ctrl, const struct rose_msg_invoke *inv
 {
 	struct pri_subcommand *subcmd;
 
-	if (!PRI_MASTER(ctrl)->aoc_support) {
+	if (!ctrl->aoc_support) {
 		return;
 	}
 	subcmd = q931_alloc_subcommand(ctrl);
@@ -577,7 +577,7 @@ void aoc_etsi_aoc_d_charging_unit(struct pri *ctrl, const struct rose_msg_invoke
 {
 	struct pri_subcommand *subcmd;
 
-	if (!PRI_MASTER(ctrl)->aoc_support) {
+	if (!ctrl->aoc_support) {
 		return;
 	}
 	subcmd = q931_alloc_subcommand(ctrl);
@@ -760,7 +760,7 @@ void aoc_etsi_aoc_e_currency(struct pri *ctrl, q931_call *call, const struct ros
 {
 	struct pri_subcommand *subcmd;
 
-	if (!PRI_MASTER(ctrl)->aoc_support) {
+	if (!ctrl->aoc_support) {
 		return;
 	}
 	subcmd = q931_alloc_subcommand(ctrl);
@@ -828,7 +828,7 @@ void aoc_etsi_aoc_e_charging_unit(struct pri *ctrl, q931_call *call, const struc
 		}
 	}
 
-	if (!PRI_MASTER(ctrl)->aoc_support) {
+	if (!ctrl->aoc_support) {
 		return;
 	}
 	subcmd = q931_alloc_subcommand(ctrl);
@@ -869,7 +869,6 @@ void aoc_etsi_aoc_e_charging_unit(struct pri *ctrl, q931_call *call, const struc
 void pri_aoc_events_enable(struct pri *ctrl, int enable)
 {
 	if (ctrl) {
-		ctrl = PRI_MASTER(ctrl);
 		ctrl->aoc_support = enable ? 1 : 0;
 	}
 }
diff --git a/pri_cc.c b/pri_cc.c
index 407e24b..b68127b 100644
--- a/pri_cc.c
+++ b/pri_cc.c
@@ -61,7 +61,6 @@ struct pri_cc_record *pri_cc_find_by_reference(struct pri *ctrl, unsigned refere
 {
 	struct pri_cc_record *cc_record;
 
-	ctrl = PRI_MASTER(ctrl);
 	for (cc_record = ctrl->cc.pool; cc_record; cc_record = cc_record->next) {
 		if (cc_record->ccbs_reference_id == reference_id) {
 			/* Found the record */
@@ -85,7 +84,6 @@ struct pri_cc_record *pri_cc_find_by_linkage(struct pri *ctrl, unsigned linkage_
 {
 	struct pri_cc_record *cc_record;
 
-	ctrl = PRI_MASTER(ctrl);
 	for (cc_record = ctrl->cc.pool; cc_record; cc_record = cc_record->next) {
 		if (cc_record->call_linkage_id == linkage_id) {
 			/* Found the record */
@@ -110,7 +108,6 @@ static struct pri_cc_record *pri_cc_find_by_id(struct pri *ctrl, long cc_id)
 {
 	struct pri_cc_record *cc_record;
 
-	ctrl = PRI_MASTER(ctrl);
 	for (cc_record = ctrl->cc.pool; cc_record; cc_record = cc_record->next) {
 		if (cc_record->record_id == cc_id) {
 			/* Found the record */
@@ -234,7 +231,6 @@ struct pri_cc_record *pri_cc_find_by_addressing(struct pri *ctrl, const struct q
 	struct q931_party_address addr_a;
 	struct q931_party_address addr_b;
 
-	ctrl = PRI_MASTER(ctrl);
 	addr_a = *party_a;
 	addr_b = *party_b;
 	for (cc_record = ctrl->cc.pool; cc_record; cc_record = cc_record->next) {
@@ -266,7 +262,6 @@ static int pri_cc_new_reference_id(struct pri *ctrl)
 	long reference_id;
 	long first_id;
 
-	ctrl = PRI_MASTER(ctrl);
 	ctrl->cc.last_reference_id = (ctrl->cc.last_reference_id + 1) & 0x7F;
 	reference_id = ctrl->cc.last_reference_id;
 	first_id = reference_id;
@@ -298,7 +293,6 @@ static int pri_cc_new_linkage_id(struct pri *ctrl)
 	long linkage_id;
 	long first_id;
 
-	ctrl = PRI_MASTER(ctrl);
 	ctrl->cc.last_linkage_id = (ctrl->cc.last_linkage_id + 1) & 0x7F;
 	linkage_id = ctrl->cc.last_linkage_id;
 	first_id = linkage_id;
@@ -330,7 +324,6 @@ static long pri_cc_new_id(struct pri *ctrl)
 	long record_id;
 	long first_id;
 
-	ctrl = PRI_MASTER(ctrl);
 	record_id = ++ctrl->cc.last_record_id;
 	first_id = record_id;
 	while (pri_cc_find_by_id(ctrl, record_id)) {
@@ -386,7 +379,6 @@ static void pri_cc_delete_record(struct pri *ctrl, struct pri_cc_record *doomed)
 	}
 	pri_cc_disassociate_signaling_link(doomed);
 
-	ctrl = PRI_MASTER(ctrl);
 	for (prev = &ctrl->cc.pool, current = ctrl->cc.pool; current;
 		prev = &current->next, current = current->next) {
 		if (current == doomed) {
@@ -413,7 +405,6 @@ struct pri_cc_record *pri_cc_new_record(struct pri *ctrl, q931_call *call)
 	struct pri_cc_record *cc_record;
 	long record_id;
 
-	ctrl = PRI_MASTER(ctrl);
 	record_id = pri_cc_new_id(ctrl);
 	if (record_id < 0) {
 		return NULL;
@@ -424,7 +415,7 @@ struct pri_cc_record *pri_cc_new_record(struct pri *ctrl, q931_call *call)
 	}
 
 	/* Initialize the new record */
-	cc_record->master = ctrl;
+	cc_record->ctrl = ctrl;
 	cc_record->record_id = record_id;
 	cc_record->call_linkage_id = CC_PTMP_INVALID_ID;/* So it will never be found this way */
 	cc_record->ccbs_reference_id = CC_PTMP_INVALID_ID;/* So it will never be found this way */
@@ -975,7 +966,7 @@ static unsigned char *enc_qsig_cc_request(struct pri *ctrl,
 
 	//msg.args.qsig.CcbsRequest.can_retain_service = 0;
 
-	switch (PRI_MASTER(ctrl)->cc.option.signaling_retention_req) {
+	switch (ctrl->cc.option.signaling_retention_req) {
 	case 0:/* Want release signaling link. */
 		cc_record->option.retain_signaling_link = 0;
 
@@ -1954,7 +1945,6 @@ static unsigned char *enc_etsi_ptmp_cc_interrogate_rsp_general(struct pri *ctrl,
 	struct q931_party_number party_a_number;
 	const struct pri_cc_record *cc_record;
 	unsigned char *new_pos;
-	struct pri *master;
 	unsigned idx;
 
 	pos = facility_encode_header(ctrl, pos, end, NULL);
@@ -1966,8 +1956,7 @@ static unsigned char *enc_etsi_ptmp_cc_interrogate_rsp_general(struct pri *ctrl,
 	msg.invoke_id = invoke->invoke_id;
 	msg.operation = invoke->operation;
 
-	master = PRI_MASTER(ctrl);
-	msg.args.etsi.CCBSInterrogate.recall_mode = master->cc.option.recall_mode;
+	msg.args.etsi.CCBSInterrogate.recall_mode = ctrl->cc.option.recall_mode;
 
 	/* Convert the given party A number. */
 	q931_party_number_init(&party_a_number);
@@ -1979,7 +1968,7 @@ static unsigned char *enc_etsi_ptmp_cc_interrogate_rsp_general(struct pri *ctrl,
 
 	/* Build the CallDetails list. */
 	idx = 0;
-	for (cc_record = master->cc.pool; cc_record; cc_record = cc_record->next) {
+	for (cc_record = ctrl->cc.pool; cc_record; cc_record = cc_record->next) {
 		if (cc_record->ccbs_reference_id == CC_PTMP_INVALID_ID
 			|| (!cc_record->is_ccnr) != (invoke->operation == ROSE_ETSI_CCBSInterrogate)) {
 			/*
@@ -2087,7 +2076,7 @@ int pri_cc_interrogate_rsp(struct pri *ctrl, q931_call *call, const struct rose_
 {
 	int encode_result;
 
-	if (!PRI_MASTER(ctrl)->cc_support) {
+	if (!ctrl->cc_support) {
 		/* Call completion is disabled. */
 		return send_facility_error(ctrl, call, invoke->invoke_id,
 			ROSE_ERROR_Gen_NotSubscribed);
@@ -2134,7 +2123,7 @@ void pri_cc_ptmp_request(struct pri *ctrl, q931_call *call, const struct rose_ms
 {
 	struct pri_cc_record *cc_record;
 
-	if (!PRI_MASTER(ctrl)->cc_support) {
+	if (!ctrl->cc_support) {
 		/* Call completion is disabled. */
 		send_facility_error(ctrl, call, invoke->invoke_id,
 			ROSE_ERROR_Gen_NotSubscribed);
@@ -2191,7 +2180,7 @@ void pri_cc_ptp_request(struct pri *ctrl, q931_call *call, int msgtype, const st
 		/* Ignore CC request message since it did not come in on the correct message. */
 		return;
 	}
-	if (!PRI_MASTER(ctrl)->cc_support) {
+	if (!ctrl->cc_support) {
 		/* Call completion is disabled. */
 		rose_error_msg_encode(ctrl, call, Q931_ANY_MESSAGE, invoke->invoke_id,
 			ROSE_ERROR_Gen_NotSubscribed);
@@ -2270,7 +2259,6 @@ void pri_cc_ptp_request(struct pri *ctrl, q931_call *call, int msgtype, const st
  */
 void pri_cc_qsig_request(struct pri *ctrl, q931_call *call, int msgtype, const struct rose_msg_invoke *invoke)
 {
-	struct pri *master;
 	struct pri_cc_record *cc_record;
 	struct q931_party_address party_a;
 	struct q931_party_address party_b;
@@ -2279,8 +2267,7 @@ void pri_cc_qsig_request(struct pri *ctrl, q931_call *call, int msgtype, const s
 		/* Ignore CC request message since it did not come in on the correct message. */
 		return;
 	}
-	master = PRI_MASTER(ctrl);
-	if (!master->cc_support) {
+	if (!ctrl->cc_support) {
 		/* Call completion is disabled. */
 		rose_error_msg_encode(ctrl, call, Q931_ANY_MESSAGE, invoke->invoke_id,
 			ROSE_ERROR_QSIG_LongTermRejection);
@@ -2302,7 +2289,7 @@ void pri_cc_qsig_request(struct pri *ctrl, q931_call *call, int msgtype, const s
 	rose_copy_subaddress_to_q931(ctrl, &party_b.subaddress,
 		&invoke->args.qsig.CcbsRequest.subaddr_b);
 
-	cc_record = pri_cc_find_by_addressing(master, &party_a, &party_b,
+	cc_record = pri_cc_find_by_addressing(ctrl, &party_a, &party_b,
 		invoke->args.qsig.CcbsRequest.q931ie.length,
 		invoke->args.qsig.CcbsRequest.q931ie.contents);
 	if (!cc_record || cc_record->state != CC_STATE_AVAILABLE) {
@@ -2321,7 +2308,7 @@ void pri_cc_qsig_request(struct pri *ctrl, q931_call *call, int msgtype, const s
 	} else {
 		/* The originator does not care.  Do how we are configured. */
 		cc_record->option.retain_signaling_link =
-			master->cc.option.signaling_retention_rsp;
+			ctrl->cc.option.signaling_retention_rsp;
 	}
 	if (!cc_record->party_a.number.valid || cc_record->party_a.number.str[0] == '\0') {
 		/*
@@ -2805,7 +2792,7 @@ static void pri_cc_timeout_t_retention(void *data)
 	struct pri_cc_record *cc_record = data;
 
 	cc_record->t_retention = 0;
-	q931_cc_timeout(cc_record->master, cc_record, CC_EVENT_TIMEOUT_T_RETENTION);
+	q931_cc_timeout(cc_record->ctrl, cc_record, CC_EVENT_TIMEOUT_T_RETENTION);
 }
 
 /*!
@@ -2857,7 +2844,7 @@ static void pri_cc_timeout_extended_t_ccbs1(void *data)
 	struct pri_cc_record *cc_record = data;
 
 	cc_record->fsm.ptmp.extended_t_ccbs1 = 0;
-	q931_cc_timeout(cc_record->master, cc_record, CC_EVENT_TIMEOUT_EXTENDED_T_CCBS1);
+	q931_cc_timeout(cc_record->ctrl, cc_record, CC_EVENT_TIMEOUT_EXTENDED_T_CCBS1);
 }
 
 /*!
@@ -2911,7 +2898,7 @@ static void pri_cc_timeout_t_supervision(void *data)
 	struct pri_cc_record *cc_record = data;
 
 	cc_record->t_supervision = 0;
-	q931_cc_timeout(cc_record->master, cc_record, CC_EVENT_TIMEOUT_T_SUPERVISION);
+	q931_cc_timeout(cc_record->ctrl, cc_record, CC_EVENT_TIMEOUT_T_SUPERVISION);
 }
 
 /*!
@@ -2991,7 +2978,7 @@ static void pri_cc_timeout_t_recall(void *data)
 	struct pri_cc_record *cc_record = data;
 
 	cc_record->t_recall = 0;
-	q931_cc_timeout(cc_record->master, cc_record, CC_EVENT_TIMEOUT_T_RECALL);
+	q931_cc_timeout(cc_record->ctrl, cc_record, CC_EVENT_TIMEOUT_T_RECALL);
 }
 
 /*!
@@ -3755,7 +3742,7 @@ static void pri_cc_indirect_status_rsp_a(void *data)
 	struct pri_cc_record *cc_record = data;
 
 	cc_record->t_indirect = 0;
-	q931_cc_indirect(cc_record->master, cc_record, pri_cc_fill_status_rsp_a);
+	q931_cc_indirect(cc_record->ctrl, cc_record, pri_cc_fill_status_rsp_a);
 }
 
 /*!
@@ -3904,7 +3891,7 @@ static void pri_cc_indirect_status_a(void *data)
 	struct pri_cc_record *cc_record = data;
 
 	cc_record->t_indirect = 0;
-	q931_cc_indirect(cc_record->master, cc_record, pri_cc_fill_status_a);
+	q931_cc_indirect(cc_record->ctrl, cc_record, pri_cc_fill_status_a);
 }
 
 /*!
@@ -4261,7 +4248,7 @@ static void pri_cc_post_hangup_signaling(void *data)
 	struct pri_cc_record *cc_record = data;
 
 	cc_record->t_indirect = 0;
-	q931_cc_timeout(cc_record->master, cc_record, CC_EVENT_HANGUP_SIGNALING);
+	q931_cc_timeout(cc_record->ctrl, cc_record, CC_EVENT_HANGUP_SIGNALING);
 }
 
 /*!
@@ -6850,7 +6837,7 @@ long pri_cc_available(struct pri *ctrl, q931_call *call)
 				break;
 			}
 			cc_record->call_linkage_id = linkage_id;
-			cc_record->signaling = PRI_MASTER(ctrl)->dummy_call;
+			cc_record->signaling = ctrl->link.dummy_call;
 		} else {
 			cc_record = pri_cc_new_record(ctrl, call);
 			if (!cc_record) {
@@ -6894,7 +6881,7 @@ void pri_cc_qsig_determine_available(struct pri *ctrl, q931_call *call)
 		return;
 	}
 
-	if (!PRI_MASTER(ctrl)->cc_support) {
+	if (!ctrl->cc_support) {
 		/*
 		 * Blocking the cc-available event effectively
 		 * disables call completion for outgoing calls.
diff --git a/pri_facility.c b/pri_facility.c
index dc4b5c4..f32f8f1 100644
--- a/pri_facility.c
+++ b/pri_facility.c
@@ -1859,7 +1859,7 @@ int pri_mwi_indicate(struct pri *ctrl, const struct pri_party_id *mailbox,
 		if (!BRI_NT_PTMP(ctrl)) {
 			return -1;
 		}
-		call = PRI_MASTER(ctrl)->dummy_call;
+		call = ctrl->link.dummy_call;
 		if (!call) {
 			return -1;
 		}
@@ -3825,7 +3825,6 @@ int pri_mcid_req_send(struct pri *ctrl, q931_call *call)
 void pri_mcid_enable(struct pri *ctrl, int enable)
 {
 	if (ctrl) {
-		ctrl = PRI_MASTER(ctrl);
 		ctrl->mcid_support = enable ? 1 : 0;
 	}
 }
@@ -3882,7 +3881,7 @@ void rose_handle_reject(struct pri *ctrl, q931_call *call, int msgtype, q931_ie
 		 * Look for the original invocation message on the
 		 * broadcast dummy call reference call first.
 		 */
-		orig_call = PRI_MASTER(ctrl)->dummy_call;
+		orig_call = ctrl->link.dummy_call;
 		if (orig_call) {
 			apdu = pri_call_apdu_find(orig_call, reject->invoke_id);
 		}
@@ -3966,7 +3965,7 @@ void rose_handle_error(struct pri *ctrl, q931_call *call, int msgtype, q931_ie *
 		 * Look for the original invocation message on the
 		 * broadcast dummy call reference call first.
 		 */
-		orig_call = PRI_MASTER(ctrl)->dummy_call;
+		orig_call = ctrl->link.dummy_call;
 		if (orig_call) {
 			apdu = pri_call_apdu_find(orig_call, error->invoke_id);
 		}
@@ -4042,7 +4041,7 @@ void rose_handle_result(struct pri *ctrl, q931_call *call, int msgtype, q931_ie
 		 * Look for the original invocation message on the
 		 * broadcast dummy call reference call first.
 		 */
-		orig_call = PRI_MASTER(ctrl)->dummy_call;
+		orig_call = ctrl->link.dummy_call;
 		if (orig_call) {
 			apdu = pri_call_apdu_find(orig_call, result->invoke_id);
 		}
@@ -4099,7 +4098,7 @@ void rose_handle_invoke(struct pri *ctrl, q931_call *call, int msgtype, q931_ie
 		break;
 #endif	/* Not handled yet */
 	case ROSE_ETSI_CallDeflection:
-		if (!PRI_MASTER(ctrl)->deflection_support) {
+		if (!ctrl->deflection_support) {
 			send_facility_error(ctrl, call, invoke->invoke_id,
 				ROSE_ERROR_Gen_NotSubscribed);
 			break;
@@ -4167,7 +4166,7 @@ void rose_handle_invoke(struct pri *ctrl, q931_call *call, int msgtype, q931_ie
 			&deflection);
 		break;
 	case ROSE_ETSI_CallRerouting:
-		if (!PRI_MASTER(ctrl)->deflection_support) {
+		if (!ctrl->deflection_support) {
 			send_facility_error(ctrl, call, invoke->invoke_id,
 				ROSE_ERROR_Gen_NotSubscribed);
 			break;
@@ -4365,7 +4364,7 @@ void rose_handle_invoke(struct pri *ctrl, q931_call *call, int msgtype, q931_ie
 		break;
 #endif	/* Not handled yet */
 	case ROSE_ETSI_EctExecute:
-		if (!PRI_MASTER(ctrl)->transfer_support) {
+		if (!ctrl->transfer_support) {
 			send_facility_error(ctrl, call, invoke->invoke_id,
 				ROSE_ERROR_Gen_NotSubscribed);
 			break;
@@ -4390,7 +4389,7 @@ void rose_handle_invoke(struct pri *ctrl, q931_call *call, int msgtype, q931_ie
 		break;
 #endif	/* Not handled yet */
 	case ROSE_ETSI_EctLinkIdRequest:
-		if (!PRI_MASTER(ctrl)->transfer_support) {
+		if (!ctrl->transfer_support) {
 			send_facility_error(ctrl, call, invoke->invoke_id,
 				ROSE_ERROR_Gen_ResourceUnavailable);
 			break;
@@ -4430,7 +4429,7 @@ void rose_handle_invoke(struct pri *ctrl, q931_call *call, int msgtype, q931_ie
 		break;
 #endif	/* defined(STATUS_REQUEST_PLACE_HOLDER) */
 	case ROSE_ETSI_CallInfoRetain:
-		if (!PRI_MASTER(ctrl)->cc_support) {
+		if (!ctrl->cc_support) {
 			/*
 			 * Blocking the cc-available event effectively
 			 * disables call completion for outgoing calls.
@@ -4445,7 +4444,7 @@ void rose_handle_invoke(struct pri *ctrl, q931_call *call, int msgtype, q931_ie
 		if (!cc_record) {
 			break;
 		}
-		cc_record->signaling = PRI_MASTER(ctrl)->dummy_call;
+		cc_record->signaling = ctrl->link.dummy_call;
 		/*
 		 * Since we received this facility, we will not be allocating any
 		 * reference and linkage id's.
@@ -4645,7 +4644,7 @@ void rose_handle_invoke(struct pri *ctrl, q931_call *call, int msgtype, q931_ie
 		pri_cc_event(ctrl, call, cc_record, CC_EVENT_REMOTE_USER_FREE);
 		break;
 	case ROSE_ETSI_CCBS_T_Available:
-		if (!PRI_MASTER(ctrl)->cc_support) {
+		if (!ctrl->cc_support) {
 			/*
 			 * Blocking the cc-available event effectively
 			 * disables call completion for outgoing calls.
@@ -4669,7 +4668,7 @@ void rose_handle_invoke(struct pri *ctrl, q931_call *call, int msgtype, q931_ie
 			/* Don't even dignify this with a response. */
 			break;
 		}
-		if (!PRI_MASTER(ctrl)->mcid_support) {
+		if (!ctrl->mcid_support) {
 			send_facility_error(ctrl, call, invoke->invoke_id,
 				ROSE_ERROR_Gen_NotSubscribed);
 			break;
@@ -4877,7 +4876,7 @@ void rose_handle_invoke(struct pri *ctrl, q931_call *call, int msgtype, q931_ie
 		break;
 #endif	/* Not handled yet */
 	case ROSE_QSIG_CallRerouting:
-		if (!PRI_MASTER(ctrl)->deflection_support) {
+		if (!ctrl->deflection_support) {
 			send_facility_error(ctrl, call, invoke->invoke_id,
 				ROSE_ERROR_Gen_NotSubscribed);
 			break;
diff --git a/pri_internal.h b/pri_internal.h
index c83329c..74abc58 100644
--- a/pri_internal.h
+++ b/pri_internal.h
@@ -76,8 +76,6 @@ struct pri {
 	void *userdata;
 	/*! Accumulated pri_message() line. (Valid in master record only) */
 	struct pri_msg_line *msg_line;
-	struct pri *subchannel;	/* Sub-channel if appropriate */
-	struct pri *master;		/* Master channel if appropriate */
 	struct {
 		/*! Dynamically allocated array of timers that can grow as needed. */
 		struct pri_sched *timer;
@@ -93,9 +91,8 @@ struct pri {
 	int localtype;		/* Local network type (unknown, network, cpe) */
 	int remotetype;		/* Remote network type (unknown, network, cpe) */
 
-	int sapi;
-	int tei;
-	int protodisc;
+	int protodisc;	/* Layer 3 protocol discriminator */
+
 	unsigned int nfas:1;/* TRUE if this D channel is involved with an NFAS group */
 	unsigned int bri:1;
 	unsigned int acceptinbanddisconnect:1;	/* Should we allow inband progress after DISCONNECT? */
@@ -112,57 +109,23 @@ struct pri {
 	unsigned int manual_connect_ack:1;/* TRUE if the CONNECT_ACKNOWLEDGE is sent with API call */
 	unsigned int mcid_support:1;/* TRUE if the upper layer supports MCID */
 
-	/* MDL variables */
-	int mdl_error;
-	int mdl_error_state;
-	int mdl_timer;
-	int mdl_free_me;
-
-	/* Q.921 State */
-	int q921_state;	
-	int RC;
-	int peer_rx_busy:1;
-	int own_rx_busy:1;
-	int acknowledge_pending:1;
-	int reject_exception:1;
-
-	int v_s;			/* Next N(S) for transmission */
-	int v_a;			/* Last acknowledged frame */
-	int v_r;			/* Next frame expected to be received */
+	/*! Layer 2 link control for D channel. */
+	struct q921_link link;
 	
 	int cref;			/* Next call reference value */
-	
-	int l3initiated;
-
-	/* Various timers */
-	int t203_timer;		/* Max idle time */
-	int t202_timer;
-	int n202_counter;
-	int ri;
-	int t200_timer;		/* T-200 retransmission timer */
+
 	/* All ISDN Timer values */
 	int timers[PRI_MAX_TIMERS];
 
 	/* Used by scheduler */
-	struct timeval tv;
 	int schedev;
 	pri_event ev;		/* Static event thingy */
 	/*! Subcommands for static event thingy. */
 	struct pri_subcommands subcmds;
 	
-	/* Q.921 Re-transmission queue */
-	struct q921_frame *txqueue;
-	
 	/* Q.931 calls */
-	q931_call **callpool;
-	q931_call *localpool;
-
-	/*!
-	 * \brief Q.931 Dummy call reference call associated with this TEI.
-	 * \note If present then this call is allocated as part of the
-	 * D channel control structure.
-	 */
-	q931_call *dummy_call;
+	struct q931_call **callpool;
+	struct q931_call *localpool;
 
 #ifdef LIBPRI_COUNTERS
 	/* q921/q931 packet counters */
@@ -370,10 +333,6 @@ struct pri_sr {
 	int aoc_charging_request;
 };
 
-/* Internal switch types */
-#define PRI_SWITCH_GR303_EOC_PATH	19
-#define PRI_SWITCH_GR303_TMC_SWITCHING	20
-
 #define Q931_MAX_TEI	8
 
 /*! \brief Incoming call transfer states. */
@@ -449,7 +408,7 @@ struct decoded_bc {
 /* q931_call datastructure */
 struct q931_call {
 	struct pri *pri;	/* D channel controller (master) */
-	struct pri *link;	/* Q.921 link associated with this call. */
+	struct q921_link *link;	/* Q.921 link associated with this call. */
 	struct q931_call *next;
 	int cr;				/* Call Reference */
 	/* Slotmap specified (bitmap of channels 31/24-1) (Channel Identifier IE) (-1 means not specified) */
@@ -592,7 +551,7 @@ struct q931_call {
 	int is_link_id_valid;
 
 	/* Bridged call info */
-	q931_call *bridged_call;        /* Pointer to other leg of bridged call (Used by Q.SIG when eliminating tromboned calls) */
+	struct q931_call *bridged_call;        /* Pointer to other leg of bridged call (Used by Q.SIG when eliminating tromboned calls) */
 
 	int changestatus;		/* SERVICE message changestatus */
 	int reversecharge;		/* Reverse charging indication:
@@ -746,8 +705,8 @@ enum CC_PARTY_A_AVAILABILITY {
 struct pri_cc_record {
 	/*! Next call-completion record in the list */
 	struct pri_cc_record *next;
-	/*! Master D channel control structure. */
-	struct pri *master;
+	/*! D channel control structure. */
+	struct pri *ctrl;
 	/*! Original call that is offered CC availability. (NULL if no longer exists.) */
 	struct q931_call *original_call;
 	/*!
@@ -883,6 +842,14 @@ struct d_ctrl_dummy {
 	struct q931_call dummy_call;
 };
 
+/*! Layer 2 link control structure with associated dummy call reference record. */
+struct link_dummy {
+	/*! Layer 2 control structure. Must be first in the structure. */
+	struct q921_link link;
+	/*! Dummy call reference call record. */
+	struct q931_call dummy_call;
+};
+
 /*!
  * \brief Check if the given call ptr is valid and gripe if not.
  *
@@ -912,10 +879,10 @@ void pri_error(struct pri *ctrl, const char *fmt, ...) __attribute__((format(pri
 
 void libpri_copy_string(char *dst, const char *src, size_t size);
 
-struct pri *__pri_new_tei(int fd, int node, int switchtype, struct pri *master, pri_io_cb rd, pri_io_cb wr, void *userdata, int tei, int bri);
-void __pri_free_tei(struct pri *p);
+void pri_link_destroy(struct q921_link *link);
+struct q921_link *pri_link_new(struct pri *ctrl, int sapi, int tei);
 
-void q931_init_call_record(struct pri *link, struct q931_call *call, int cr);
+void q931_init_call_record(struct q921_link *link, struct q931_call *call, int cr);
 
 void pri_sr_init(struct pri_sr *req);
 
@@ -984,21 +951,6 @@ int pri_cc_event(struct pri *ctrl, q931_call *call, struct pri_cc_record *cc_rec
 int q931_cc_timeout(struct pri *ctrl, struct pri_cc_record *cc_record, enum CC_EVENTS event);
 void q931_cc_indirect(struct pri *ctrl, struct pri_cc_record *cc_record, void (*func)(struct pri *ctrl, q931_call *call, struct pri_cc_record *cc_record));
 
-/*!
- * \brief Get the master PRI control structure.
- *
- * \param ctrl D channel controller.
- *
- * \return Master PRI control structure.
- */
-static inline struct pri *PRI_MASTER(struct pri *ctrl)
-{
-	while (ctrl->master) {
-		ctrl = ctrl->master;
-	}
-	return ctrl;
-}
-
 /*!
  * \brief Determine if layer 2 is in BRI NT PTMP mode.
  *
@@ -1011,10 +963,8 @@ static inline int BRI_NT_PTMP(const struct pri *ctrl)
 {
 	struct pri *my_ctrl = (struct pri *) ctrl;
 
-	/* Check master control structure */
-	my_ctrl = PRI_MASTER(my_ctrl);
 	return my_ctrl->bri && my_ctrl->localtype == PRI_NETWORK
-		&& my_ctrl->tei == Q921_TEI_GROUP;
+		&& my_ctrl->link.tei == Q921_TEI_GROUP;
 }
 
 /*!
@@ -1029,10 +979,8 @@ static inline int BRI_TE_PTMP(const struct pri *ctrl)
 {
 	struct pri *my_ctrl = (struct pri *) ctrl;
 
-	/* Check master control structure */
-	my_ctrl = PRI_MASTER(my_ctrl);
 	return my_ctrl->bri && my_ctrl->localtype == PRI_CPE
-		&& my_ctrl->tei == Q921_TEI_GROUP;
+		&& my_ctrl->link.tei == Q921_TEI_GROUP;
 }
 
 /*!
@@ -1047,8 +995,6 @@ static inline int NT_MODE(const struct pri *ctrl)
 {
 	struct pri *my_ctrl = (struct pri *) ctrl;
 
-	/* Check master control structure */
-	my_ctrl = PRI_MASTER(my_ctrl);
 	return my_ctrl->localtype == PRI_NETWORK;
 }
 
@@ -1064,8 +1010,6 @@ static inline int TE_MODE(const struct pri *ctrl)
 {
 	struct pri *my_ctrl = (struct pri *) ctrl;
 
-	/* Check master control structure */
-	my_ctrl = PRI_MASTER(my_ctrl);
 	return my_ctrl->localtype == PRI_CPE;
 }
 
@@ -1081,9 +1025,7 @@ static inline int PTP_MODE(const struct pri *ctrl)
 {
 	struct pri *my_ctrl = (struct pri *) ctrl;
 
-	/* Check master control structure */
-	my_ctrl = PRI_MASTER(my_ctrl);
-	return my_ctrl->tei == Q921_TEI_PRI;
+	return my_ctrl->link.tei == Q921_TEI_PRI;
 }
 
 /*!
@@ -1098,9 +1040,7 @@ static inline int PTMP_MODE(const struct pri *ctrl)
 {
 	struct pri *my_ctrl = (struct pri *) ctrl;
 
-	/* Check master control structure */
-	my_ctrl = PRI_MASTER(my_ctrl);
-	return my_ctrl->tei == Q921_TEI_GROUP;
+	return my_ctrl->link.tei == Q921_TEI_GROUP;
 }
 
 #define Q931_DUMMY_CALL_REFERENCE	-1
@@ -1112,14 +1052,13 @@ static inline int PTMP_MODE(const struct pri *ctrl)
  * \retval TRUE if given call is a dummy call.
  * \retval FALSE otherwise.
  */
-static inline int q931_is_dummy_call(const q931_call *call)
+static inline int q931_is_dummy_call(const struct q931_call *call)
 {
 	return (call->cr == Q931_DUMMY_CALL_REFERENCE) ? 1 : 0;
 }
 
 static inline short get_invokeid(struct pri *ctrl)
 {
-	ctrl = PRI_MASTER(ctrl);
 	return ++ctrl->last_invoke;
 }
 
diff --git a/pri_q921.h b/pri_q921.h
index 12d3997..46a0d28 100644
--- a/pri_q921.h
+++ b/pri_q921.h
@@ -180,6 +180,66 @@ typedef enum q921_state {
 	Q921_TIMER_RECOVERY = 8,
 } q921_state;
 
+/*! \brief Q.921 link controller structure */
+struct q921_link {
+	/*! Next Q.921 link in the chain. */
+	struct q921_link *next;
+	/*! D channel controller associated with this link. */
+	struct pri *ctrl;
+
+	/*!
+	 * \brief Q.931 Dummy call reference call associated with this TEI.
+	 *
+	 * \note If present then this call is allocated with the D
+	 * channel control structure or the link control structure
+	 * unless this is the TE PTMP broadcast TEI or a GR303 link.
+	 */
+	struct q931_call *dummy_call;
+
+	/*! Q.921 Re-transmission queue */
+	struct q921_frame *tx_queue;
+
+	/*! Q.921 State */
+	enum q921_state state;
+
+	/*! Service Access Profile Identifier (SAPI) of this link */
+	int sapi;
+	/*! Terminal Endpoint Identifier (TEI) of this link */
+	int tei;
+	/*! TEI assignment random indicator. */
+	int ri;
+
+	/*! V(A) - Next I-frame sequence number needing ack */
+	int v_a;
+	/*! V(S) - Next I-frame sequence number to send */
+	int v_s;
+	/*! V(R) - Next I-frame sequence number expected to receive */
+	int v_r;
+
+	/* Various timers */
+
+	/*! T-200 retransmission timer */
+	int t200_timer;
+	/*! Retry Count (T200) */
+	int RC;
+	int t202_timer;
+	int n202_counter;
+	/*! Max idle time */
+	int t203_timer;
+
+	/* MDL variables */
+	int mdl_timer;
+	int mdl_error;
+	enum q921_state mdl_error_state;
+	unsigned int mdl_free_me:1;
+
+	unsigned int peer_rx_busy:1;
+	unsigned int own_rx_busy:1;
+	unsigned int acknowledge_pending:1;
+	unsigned int reject_exception:1;
+	unsigned int l3_initiated:1;
+};
+
 static inline int Q921_ADD(int a, int b)
 {
 	return (a + b) % 128;
@@ -189,15 +249,15 @@ static inline int Q921_ADD(int a, int b)
 extern void q921_dump(struct pri *pri, q921_h *h, int len, int showraw, int txrx);
 
 /* Bring up the D-channel */
-void q921_start(struct pri *link);
+void q921_start(struct q921_link *link);
 
 //extern void q921_reset(struct pri *pri, int reset_iqueue);
 
 extern pri_event *q921_receive(struct pri *pri, q921_h *h, int len);
 
-int q921_transmit_iframe(struct pri *link, void *buf, int len, int cr);
+int q921_transmit_iframe(struct q921_link *link, void *buf, int len, int cr);
 
-int q921_transmit_uiframe(struct pri *link, void *buf, int len);
+int q921_transmit_uiframe(struct q921_link *link, void *buf, int len);
 
 extern pri_event *q921_dchannel_up(struct pri *pri);
 
diff --git a/pri_q931.h b/pri_q931.h
index aed19bd..7704407 100644
--- a/pri_q931.h
+++ b/pri_q931.h
@@ -454,7 +454,7 @@ extern int maintenance_service(struct pri *pri, int span, int channel, int chang
 /* Q.SIG specific */
 #define QSIG_IE_TRANSIT_COUNT		0x31
 
-int q931_receive(struct pri *link, q931_h *h, int len);
+int q931_receive(struct q921_link *link, q931_h *h, int len);
 
 extern int q931_alerting(struct pri *pri, q931_call *call, int channel, int info);
 
@@ -507,7 +507,7 @@ enum Q931_DL_EVENT {
 	Q931_DL_EVENT_DL_RELEASE_CONFIRM,
 	Q931_DL_EVENT_TEI_REMOVAL,
 };
-void q931_dl_event(struct pri *link, enum Q931_DL_EVENT event);
+void q931_dl_event(struct q921_link *link, enum Q931_DL_EVENT event);
 
 int q931_send_hold(struct pri *ctrl, struct q931_call *call);
 int q931_send_hold_ack(struct pri *ctrl, struct q931_call *call);
diff --git a/prisched.c b/prisched.c
index 08b28f6..cc5845e 100644
--- a/prisched.c
+++ b/prisched.c
@@ -112,9 +112,6 @@ int pri_schedule_event(struct pri *ctrl, int ms, void (*function)(void *data), v
 	unsigned x;
 	struct timeval tv;
 
-	/* Scheduling runs on master channels only */
-	ctrl = PRI_MASTER(ctrl);
-
 	max_used = ctrl->sched.max_used;
 	for (x = 0; x < max_used; ++x) {
 		if (!ctrl->sched.timer[x].callback) {
@@ -156,9 +153,6 @@ struct timeval *pri_schedule_next(struct pri *ctrl)
 	struct timeval *closest = NULL;
 	unsigned x;
 
-	/* Scheduling runs on master channels only */
-	ctrl = PRI_MASTER(ctrl);
-
 	/* Scan the scheduled timer slots backwards so we can update the max_used value. */
 	for (x = ctrl->sched.max_used; x--;) {
 		if (ctrl->sched.timer[x].callback) {
@@ -196,9 +190,6 @@ static pri_event *__pri_schedule_run(struct pri *ctrl, struct timeval *tv)
 	void (*callback)(void *);
 	void *data;
 
-	/* Scheduling runs on master channels only */
-	ctrl = PRI_MASTER(ctrl);
-
 	max_used = ctrl->sched.max_used;
 	for (x = 0; x < max_used; ++x) {
 		if (ctrl->sched.timer[x].callback
@@ -246,9 +237,6 @@ pri_event *pri_schedule_run(struct pri *ctrl)
  */
 void pri_schedule_del(struct pri *ctrl, int id)
 {
-	/* Scheduling runs on master channels only */
-	ctrl = PRI_MASTER(ctrl);
-
 	if (0 < id && id <= ctrl->sched.num_slots) {
 		ctrl->sched.timer[id - 1].callback = NULL;
 	} else if (id) {
@@ -271,9 +259,6 @@ void pri_schedule_del(struct pri *ctrl, int id)
  */
 int pri_schedule_check(struct pri *ctrl, int id, void (*function)(void *data), void *data)
 {
-	/* Scheduling runs on master channels only */
-	ctrl = PRI_MASTER(ctrl);
-
 	if (0 < id && id <= ctrl->sched.num_slots) {
 		if (ctrl->sched.timer[id - 1].callback == function
 			&& ctrl->sched.timer[id - 1].data == data) {
diff --git a/q921.c b/q921.c
index 924cb0a..8dad1ca 100644
--- a/q921.c
+++ b/q921.c
@@ -53,11 +53,11 @@
 	(hf).h.tei = (link)->tei; \
 } while(0)
 
-static void q921_dump_pri(struct pri *link, char direction_tag);
-static void q921_establish_data_link(struct pri *link);
-static void q921_mdl_error(struct pri *link, char error);
-static void q921_mdl_remove(struct pri *link);
-static void q921_restart_ptp_link_if_needed(struct pri *link);
+static void q921_dump_pri(struct q921_link *link, char direction_tag);
+static void q921_establish_data_link(struct q921_link *link);
+static void q921_mdl_error(struct q921_link *link, char error);
+static void q921_mdl_remove(struct q921_link *link);
+static void q921_restart_ptp_link_if_needed(struct q921_link *link);
 
 /*!
  * \internal
@@ -91,11 +91,11 @@ static const char *q921_state2str(enum q921_state state)
 	return "Unknown state";
 }
 
-static void q921_setstate(struct pri *link, int newstate)
+static void q921_setstate(struct q921_link *link, int newstate)
 {
 	struct pri *ctrl;
 
-	ctrl = PRI_MASTER(link);
+	ctrl = link->ctrl;
 	if (ctrl->debug & PRI_DEBUG_Q921_STATE) {
 		/*
 		 * Suppress displaying these state transitions:
@@ -104,14 +104,14 @@ static void q921_setstate(struct pri *link, int newstate)
 		 * Q921 keeps flipping back and forth between these two states
 		 * when it has nothing better to do.
 		 */
-		switch (link->q921_state) {
+		switch (link->state) {
 		case Q921_MULTI_FRAME_ESTABLISHED:
 		case Q921_TIMER_RECOVERY:
 			switch (newstate) {
 			case Q921_MULTI_FRAME_ESTABLISHED:
 			case Q921_TIMER_RECOVERY:
 				/* Suppress displaying this state transition. */
-				link->q921_state = newstate;
+				link->state = newstate;
 				return;
 			default:
 				break;
@@ -120,27 +120,27 @@ static void q921_setstate(struct pri *link, int newstate)
 		default:
 			break;
 		}
-		if (link->q921_state != newstate) {
+		if (link->state != newstate) {
 			pri_message(ctrl, "Changing from state %d(%s) to %d(%s)\n",
-				link->q921_state, q921_state2str(link->q921_state),
+				link->state, q921_state2str(link->state),
 				newstate, q921_state2str(newstate));
 		}
 	}
-	link->q921_state = newstate;
+	link->state = newstate;
 }
 
-static void q921_discard_iqueue(struct pri *link)
+static void q921_discard_iqueue(struct q921_link *link)
 {
 	struct q921_frame *f, *p;
 
-	f = link->txqueue;
+	f = link->tx_queue;
 	while (f) {
 		p = f;
 		f = f->next;
 		/* Free frame */
 		free(p);
 	}
-	link->txqueue = NULL;
+	link->tx_queue = NULL;
 }
 
 static int q921_transmit(struct pri *ctrl, q921_h *h, int len) 
@@ -168,12 +168,12 @@ static int q921_transmit(struct pri *ctrl, q921_h *h, int len)
 	return 0;
 }
 
-static void q921_send_tei(struct pri *link, int message, int ri, int ai, int iscommand)
+static void q921_send_tei(struct pri *ctrl, int message, int ri, int ai, int iscommand)
 {
 	q921_u *f;
-	struct pri *ctrl;
+	struct q921_link *link;
 
-	ctrl = PRI_MASTER(link);
+	link = &ctrl->link;
 
 	if (!(f = calloc(1, sizeof(*f) + 5)))
 		return;
@@ -195,10 +195,10 @@ static void q921_send_tei(struct pri *link, int message, int ri, int ai, int isc
 
 static void t202_expire(void *vlink)
 {
-	struct pri *link = vlink;
+	struct q921_link *link = vlink;
 	struct pri *ctrl;
 
-	ctrl = PRI_MASTER(link);
+	ctrl = link->ctrl;
 
 	/* Start the TEI request timer. */
 	pri_schedule_del(ctrl, link->t202_timer);
@@ -214,8 +214,8 @@ static void t202_expire(void *vlink)
 			link->t202_timer = 0;
 		}
 		pri_error(ctrl, "Unable to receive TEI from network in state %d(%s)!\n",
-			link->q921_state, q921_state2str(link->q921_state));
-		switch (link->q921_state) {
+			link->state, q921_state2str(link->state));
+		switch (link->state) {
 		case Q921_ASSIGN_AWAITING_TEI:
 			break;
 		case Q921_ESTABLISH_AWAITING_TEI:
@@ -235,18 +235,18 @@ static void t202_expire(void *vlink)
 	q921_send_tei(ctrl, Q921_TEI_IDENTITY_REQUEST, link->ri, Q921_TEI_GROUP, 1);
 }
 
-static void q921_tei_request(struct pri *link)
+static void q921_tei_request(struct q921_link *link)
 {
 	link->n202_counter = 0;
 	t202_expire(link);
 }
 
-static void q921_send_dm(struct pri *link, int fbit)
+static void q921_send_dm(struct q921_link *link, int fbit)
 {
 	q921_h h;
 	struct pri *ctrl;
 
-	ctrl = PRI_MASTER(link);
+	ctrl = link->ctrl;
 
 	Q921_INIT(link, h);
 	h.u.m3 = 0;	/* M3 = 0 */
@@ -270,12 +270,12 @@ static void q921_send_dm(struct pri *link, int fbit)
 	q921_transmit(ctrl, &h, 4);
 }
 
-static void q921_send_disc(struct pri *link, int pbit)
+static void q921_send_disc(struct q921_link *link, int pbit)
 {
 	q921_h h;
 	struct pri *ctrl;
 
-	ctrl = PRI_MASTER(link);
+	ctrl = link->ctrl;
 
 	Q921_INIT(link, h);
 	h.u.m3 = 2;	/* M3 = 2 */
@@ -299,12 +299,12 @@ static void q921_send_disc(struct pri *link, int pbit)
 	q921_transmit(ctrl, &h, 4);
 }
 
-static void q921_send_ua(struct pri *link, int fbit)
+static void q921_send_ua(struct q921_link *link, int fbit)
 {
 	q921_h h;
 	struct pri *ctrl;
 
-	ctrl = PRI_MASTER(link);
+	ctrl = link->ctrl;
 
 	Q921_INIT(link, h);
 	h.u.m3 = 3;		/* M3 = 3 */
@@ -328,12 +328,12 @@ static void q921_send_ua(struct pri *link, int fbit)
 	q921_transmit(ctrl, &h, 3);
 }
 
-static void q921_send_sabme(struct pri *link)
+static void q921_send_sabme(struct q921_link *link)
 {
 	q921_h h;
 	struct pri *ctrl;
 
-	ctrl = PRI_MASTER(link);
+	ctrl = link->ctrl;
 
 	Q921_INIT(link, h);
 	h.u.m3 = 3;	/* M3 = 3 */
@@ -357,15 +357,15 @@ static void q921_send_sabme(struct pri *link)
 	q921_transmit(ctrl, &h, 3);
 }
 
-static int q921_ack_packet(struct pri *link, int num)
+static int q921_ack_packet(struct q921_link *link, int num)
 {
 	struct q921_frame *f;
 	struct q921_frame *prev;
 	struct pri *ctrl;
 
-	ctrl = PRI_MASTER(link);
+	ctrl = link->ctrl;
 
-	for (prev = NULL, f = link->txqueue; f; prev = f, f = f->next) {
+	for (prev = NULL, f = link->tx_queue; f; prev = f, f = f->next) {
 		if (!f->transmitted) {
 			break;
 		}
@@ -375,14 +375,14 @@ static int q921_ack_packet(struct pri *link, int num)
 			if (prev)
 				prev->next = f->next;
 			else
-				link->txqueue = f->next;
+				link->tx_queue = f->next;
 			if (ctrl->debug & PRI_DEBUG_Q921_DUMP) {
 				pri_message(ctrl,
-					"-- ACKing N(S)=%d, txqueue head is N(S)=%d (-1 is empty, -2 is not transmitted)\n",
+					"-- ACKing N(S)=%d, tx_queue head is N(S)=%d (-1 is empty, -2 is not transmitted)\n",
 					f->h.n_s,
-					link->txqueue
-						? link->txqueue->transmitted
-							? link->txqueue->h.n_s
+					link->tx_queue
+						? link->tx_queue->transmitted
+							? link->tx_queue->h.n_s
 							: -2
 						: -1);
 			}
@@ -398,11 +398,11 @@ static void t203_expire(void *vlink);
 static void t200_expire(void *vlink);
 
 #define restart_t200(link) reschedule_t200(link)
-static void reschedule_t200(struct pri *link)
+static void reschedule_t200(struct q921_link *link)
 {
 	struct pri *ctrl;
 
-	ctrl = PRI_MASTER(link);
+	ctrl = link->ctrl;
 
 	if (ctrl->debug & PRI_DEBUG_Q921_DUMP)
 		pri_message(ctrl, "-- Restarting T200 timer\n");
@@ -411,11 +411,11 @@ static void reschedule_t200(struct pri *link)
 }
 
 #if 0
-static void reschedule_t203(struct pri *link)
+static void reschedule_t203(struct q921_link *link)
 {
 	struct pri *ctrl;
 
-	ctrl = PRI_MASTER(link);
+	ctrl = link->ctrl;
 
 	if (ctrl->debug & PRI_DEBUG_Q921_DUMP)
 		pri_message(ctrl, "-- Restarting T203 timer\n");
@@ -425,9 +425,9 @@ static void reschedule_t203(struct pri *link)
 #endif
 
 #if 0
-static int q921_unacked_iframes(struct pri *link)
+static int q921_unacked_iframes(struct q921_link *link)
 {
-	struct q921_frame *f = link->txqueue;
+	struct q921_frame *f = link->tx_queue;
 	int cnt = 0;
 
 	while(f) {
@@ -440,11 +440,11 @@ static int q921_unacked_iframes(struct pri *link)
 }
 #endif
 
-static void start_t203(struct pri *link)
+static void start_t203(struct q921_link *link)
 {
 	struct pri *ctrl;
 
-	ctrl = PRI_MASTER(link);
+	ctrl = link->ctrl;
 
 	if (link->t203_timer) {
 		if (ctrl->debug & PRI_DEBUG_Q921_DUMP)
@@ -456,11 +456,11 @@ static void start_t203(struct pri *link)
 	link->t203_timer = pri_schedule_event(ctrl, ctrl->timers[PRI_TIMER_T203], t203_expire, link);
 }
 
-static void stop_t203(struct pri *link)
+static void stop_t203(struct q921_link *link)
 {
 	struct pri *ctrl;
 
-	ctrl = PRI_MASTER(link);
+	ctrl = link->ctrl;
 
 	if (link->t203_timer) {
 		if (ctrl->debug & PRI_DEBUG_Q921_DUMP)
@@ -473,11 +473,11 @@ static void stop_t203(struct pri *link)
 	}
 }
 
-static void start_t200(struct pri *link)
+static void start_t200(struct q921_link *link)
 {
 	struct pri *ctrl;
 
-	ctrl = PRI_MASTER(link);
+	ctrl = link->ctrl;
 
 	if (link->t200_timer) {
 		if (ctrl->debug & PRI_DEBUG_Q921_DUMP)
@@ -489,11 +489,11 @@ static void start_t200(struct pri *link)
 	link->t200_timer = pri_schedule_event(ctrl, ctrl->timers[PRI_TIMER_T200], t200_expire, link);
 }
 
-static void stop_t200(struct pri *link)
+static void stop_t200(struct q921_link *link)
 {
 	struct pri *ctrl;
 
-	ctrl = PRI_MASTER(link);
+	ctrl = link->ctrl;
 
 	if (link->t200_timer) {
 		if (ctrl->debug & PRI_DEBUG_Q921_DUMP)
@@ -507,15 +507,15 @@ static void stop_t200(struct pri *link)
 }
 
 /* This is the equivalent of the I-Frame queued up path in Figure B.7 in MULTI_FRAME_ESTABLISHED */
-static int q921_send_queued_iframes(struct pri *link)
+static int q921_send_queued_iframes(struct q921_link *link)
 {
 	struct pri *ctrl;
 	struct q921_frame *f;
 	int frames_txd = 0;
 
-	ctrl = PRI_MASTER(link);
+	ctrl = link->ctrl;
 
-	for (f = link->txqueue; f; f = f->next) {
+	for (f = link->tx_queue; f; f = f->next) {
 		if (!f->transmitted) {
 			/* This frame has not been sent yet. */
 			break;
@@ -591,12 +591,12 @@ static int q921_send_queued_iframes(struct pri *link)
 	return frames_txd;
 }
 
-static void q921_reject(struct pri *link, int pf)
+static void q921_reject(struct q921_link *link, int pf)
 {
 	q921_h h;
 	struct pri *ctrl;
 
-	ctrl = PRI_MASTER(link);
+	ctrl = link->ctrl;
 
 	Q921_INIT(link, h);
 	h.s.x0 = 0;	/* Always 0 */
@@ -621,12 +621,12 @@ static void q921_reject(struct pri *link, int pf)
 	q921_transmit(ctrl, &h, 4);
 }
 
-static void q921_rr(struct pri *link, int pbit, int cmd)
+static void q921_rr(struct q921_link *link, int pbit, int cmd)
 {
 	q921_h h;
 	struct pri *ctrl;
 
-	ctrl = PRI_MASTER(link);
+	ctrl = link->ctrl;
 
 	Q921_INIT(link, h);
 	h.s.x0 = 0;	/* Always 0 */
@@ -659,7 +659,7 @@ static void q921_rr(struct pri *link, int pbit, int cmd)
 	q921_transmit(ctrl, &h, 4);
 }
 
-static void transmit_enquiry(struct pri *link)
+static void transmit_enquiry(struct q921_link *link)
 {
 	if (!link->own_rx_busy) {
 		q921_rr(link, 1, 1);
@@ -672,10 +672,10 @@ static void transmit_enquiry(struct pri *link)
 
 static void t200_expire(void *vlink)
 {
-	struct pri *link = vlink;
+	struct q921_link *link = vlink;
 	struct pri *ctrl;
 
-	ctrl = PRI_MASTER(link);
+	ctrl = link->ctrl;
 
 	if (ctrl->debug & PRI_DEBUG_Q921_DUMP) {
 		pri_message(ctrl, "%s\n", __FUNCTION__);
@@ -684,7 +684,7 @@ static void t200_expire(void *vlink)
 
 	link->t200_timer = 0;
 
-	switch (link->q921_state) {
+	switch (link->state) {
 	case Q921_MULTI_FRAME_ESTABLISHED:
 		link->RC = 0;
 		transmit_enquiry(link);
@@ -707,7 +707,7 @@ static void t200_expire(void *vlink)
 		} else {
 			q921_mdl_error(link, 'I');
 			q921_establish_data_link(link);
-			link->l3initiated = 0;
+			link->l3_initiated = 0;
 			q921_setstate(link, Q921_AWAITING_ESTABLISHMENT);
 		}
 		break;
@@ -739,19 +739,19 @@ static void t200_expire(void *vlink)
 	default:
 		/* Looks like someone forgot to stop the T200 timer. */
 		pri_error(ctrl, "T200 expired in state %d(%s)\n",
-			link->q921_state, q921_state2str(link->q921_state));
+			link->state, q921_state2str(link->state));
 		break;
 	}
 }
 
 /* This is sending a DL-UNIT-DATA request */
-int q921_transmit_uiframe(struct pri *link, void *buf, int len)
+int q921_transmit_uiframe(struct q921_link *link, void *buf, int len)
 {
 	uint8_t ubuf[512];
 	q921_h *h = (void *)&ubuf[0];
 	struct pri *ctrl;
 
-	ctrl = PRI_MASTER(link);
+	ctrl = link->ctrl;
 
 	if (len >= 512) {
 		pri_error(ctrl, "Requested to send UI-frame larger than 512 bytes!\n");
@@ -787,23 +787,25 @@ int q921_transmit_uiframe(struct pri *link, void *buf, int len)
 	return 0;
 }
 
-static struct pri *pri_find_tei(struct pri *ctrl, int sapi, int tei)
+static struct q921_link *pri_find_tei(struct pri *ctrl, int sapi, int tei)
 {
-	for (; ctrl; ctrl = ctrl->subchannel) {
-		if (ctrl->tei == tei && ctrl->sapi == sapi)
-			return ctrl;
+	struct q921_link *link;
+
+	for (link = &ctrl->link; link; link = link->next) {
+		if (link->tei == tei && link->sapi == sapi)
+			return link;
 	}
 
 	return NULL;
 }
 
 /* This is the equivalent of a DL-DATA request, as well as the I-frame queued up outcome */
-int q921_transmit_iframe(struct pri *link, void *buf, int len, int cr)
+int q921_transmit_iframe(struct q921_link *link, void *buf, int len, int cr)
 {
 	q921_frame *f, *prev=NULL;
 	struct pri *ctrl;
 
-	ctrl = PRI_MASTER(link);
+	ctrl = link->ctrl;
 
 	if (PTMP_MODE(ctrl)) {
 		if (link->tei == Q921_TEI_GROUP) {
@@ -811,7 +813,7 @@ int q921_transmit_iframe(struct pri *link, void *buf, int len, int cr)
 			return 0;
 		}
 		if (BRI_TE_PTMP(ctrl)) {
-			switch (link->q921_state) {
+			switch (link->state) {
 			case Q921_TEI_UNASSIGNED:
 				q921_setstate(link, Q921_ESTABLISH_AWAITING_TEI);
 				q921_tei_request(link);
@@ -828,11 +830,11 @@ int q921_transmit_iframe(struct pri *link, void *buf, int len, int cr)
 	}
 
 	/* Figure B.7/Q.921 Page 70 */
-	switch (link->q921_state) {
+	switch (link->state) {
 	case Q921_TEI_ASSIGNED:
 		/* If we aren't in a state compatiable with DL-DATA requests, start getting us there here */
 		q921_establish_data_link(link);
-		link->l3initiated = 1;
+		link->l3_initiated = 1;
 		q921_setstate(link, Q921_AWAITING_ESTABLISHMENT);
 		/* For all rest, we've done the work to get us up prior to this and fall through */
 	case Q921_ESTABLISH_AWAITING_TEI:
@@ -840,7 +842,7 @@ int q921_transmit_iframe(struct pri *link, void *buf, int len, int cr)
 	case Q921_AWAITING_ESTABLISHMENT:
 	case Q921_MULTI_FRAME_ESTABLISHED:
 		/* Find queue tail. */
-		for (f = link->txqueue; f; f = f->next) {
+		for (f = link->tx_queue; f; f = f->next) {
 			prev = f;
 		}
 
@@ -870,14 +872,14 @@ int q921_transmit_iframe(struct pri *link, void *buf, int len, int cr)
 			if (prev)
 				prev->next = f;
 			else
-				link->txqueue = f;
+				link->tx_queue = f;
 
-			if (link->q921_state != Q921_MULTI_FRAME_ESTABLISHED) {
+			if (link->state != Q921_MULTI_FRAME_ESTABLISHED) {
 				if (ctrl->debug & PRI_DEBUG_Q921_STATE) {
 					pri_message(ctrl,
 						"TEI=%d Just queued I-frame since in state %d(%s)\n",
 						link->tei,
-						link->q921_state, q921_state2str(link->q921_state));
+						link->state, q921_state2str(link->state));
 				}
 				break;
 			}
@@ -902,7 +904,7 @@ int q921_transmit_iframe(struct pri *link, void *buf, int len, int cr)
 	case Q921_AWAITING_RELEASE:
 	default:
 		pri_error(ctrl, "Cannot transmit frames in state %d(%s)\n",
-			link->q921_state, q921_state2str(link->q921_state));
+			link->state, q921_state2str(link->state));
 		break;
 	}
 	return 0;
@@ -910,17 +912,17 @@ int q921_transmit_iframe(struct pri *link, void *buf, int len, int cr)
 
 static void t203_expire(void *vlink)
 {
-	struct pri *link = vlink;
+	struct q921_link *link = vlink;
 	struct pri *ctrl;
 
-	ctrl = PRI_MASTER(link);
+	ctrl = link->ctrl;
 
 	if (ctrl->debug & PRI_DEBUG_Q921_DUMP)
 		pri_message(ctrl, "%s\n", __FUNCTION__);
 
 	link->t203_timer = 0;
 
-	switch (link->q921_state) {
+	switch (link->state) {
 	case Q921_MULTI_FRAME_ESTABLISHED:
 		transmit_enquiry(link);
 		link->RC = 0;
@@ -929,22 +931,22 @@ static void t203_expire(void *vlink)
 	default:
 		/* Looks like someone forgot to stop the T203 timer. */
 		pri_error(ctrl, "T203 expired in state %d(%s)\n",
-			link->q921_state, q921_state2str(link->q921_state));
+			link->state, q921_state2str(link->state));
 		break;
 	}
 }
 
-static void q921_dump_iqueue_info(struct pri *link)
+static void q921_dump_iqueue_info(struct q921_link *link)
 {
 	struct pri *ctrl;
 	struct q921_frame *f;
 	int pending = 0, unacked = 0;
 
-	ctrl = PRI_MASTER(link);
+	ctrl = link->ctrl;
 
 	unacked = pending = 0;
 
-	for (f = link->txqueue; f; f = f->next) {
+	for (f = link->tx_queue; f; f = f->next) {
 		if (f->transmitted) {
 			unacked++;
 		} else {
@@ -1131,18 +1133,18 @@ void q921_dump(struct pri *ctrl, q921_h *h, int len, int showraw, int txrx)
 	}
 }
 
-static void q921_dump_pri(struct pri *link, char direction_tag)
+static void q921_dump_pri(struct q921_link *link, char direction_tag)
 {
 	struct pri *ctrl;
 
-	ctrl = PRI_MASTER(link);
+	ctrl = link->ctrl;
 
 	pri_message(ctrl, "%c TEI: %d State %d(%s)\n",
-		direction_tag, link->tei, link->q921_state, q921_state2str(link->q921_state));
+		direction_tag, link->tei, link->state, q921_state2str(link->state));
 	pri_message(ctrl, "%c V(A)=%d, V(S)=%d, V(R)=%d\n",
 		direction_tag, link->v_a, link->v_s, link->v_r);
-	pri_message(ctrl, "%c K=%d, RC=%d, l3initiated=%d, reject_except=%d, ack_pend=%d\n",
-		direction_tag, ctrl->timers[PRI_TIMER_K], link->RC, link->l3initiated,
+	pri_message(ctrl, "%c K=%d, RC=%d, l3_initiated=%d, reject_except=%d, ack_pend=%d\n",
+		direction_tag, ctrl->timers[PRI_TIMER_K], link->RC, link->l3_initiated,
 		link->reject_exception, link->acknowledge_pending);
 	pri_message(ctrl, "%c T200_id=%d, N200=%d, T203_id=%d\n",
 		direction_tag, link->t200_timer, ctrl->timers[PRI_TIMER_N200], link->t203_timer);
@@ -1150,7 +1152,7 @@ static void q921_dump_pri(struct pri *link, char direction_tag)
 
 static void q921_dump_pri_by_h(struct pri *ctrl, char direction_tag, q921_h *h)
 {
-	struct pri *link;
+	struct q921_link *link;
 
 	if (!ctrl) {
 		return;
@@ -1159,9 +1161,10 @@ static void q921_dump_pri_by_h(struct pri *ctrl, char direction_tag, q921_h *h)
 	if (BRI_NT_PTMP(ctrl)) {
 		link = pri_find_tei(ctrl, h->h.sapi, h->h.tei);
 	} else if (BRI_TE_PTMP(ctrl)) {
-		link = ctrl->subchannel;
+		/* We're operating on the specific TEI link */
+		link = ctrl->link.next;
 	} else {
-		link = ctrl;
+		link = &ctrl->link;
 	}
 
 	if (link) {
@@ -1174,8 +1177,8 @@ static void q921_dump_pri_by_h(struct pri *ctrl, char direction_tag, q921_h *h)
 static pri_event *q921_receive_MDL(struct pri *ctrl, q921_u *h, int len)
 {
 	int ri;
-	struct pri *sub;
-	struct pri *link;
+	struct q921_link *sub;
+	struct q921_link *link;
 	pri_event *res = NULL;
 	int tei;
 
@@ -1213,8 +1216,8 @@ static pri_event *q921_receive_MDL(struct pri *ctrl, q921_u *h, int len)
 		/* Find a TEI that is not allocated. */
 		tei = 64;
 		do {
-			for (sub = ctrl; sub->subchannel; sub = sub->subchannel) {
-				if (sub->subchannel->tei == tei) {
+			for (sub = &ctrl->link; sub->next; sub = sub->next) {
+				if (sub->next->tei == tei) {
 					/* This TEI is already assigned, try next one. */
 					++tei;
 					if (tei < Q921_TEI_GROUP) {
@@ -1225,27 +1228,27 @@ static pri_event *q921_receive_MDL(struct pri *ctrl, q921_u *h, int len)
 					return NULL;
 				}
 			}
-		} while (sub->subchannel);
+		} while (sub->next);
 
 		if (ctrl->debug & PRI_DEBUG_Q921_STATE) {
 			pri_message(ctrl, "Allocating new TEI %d\n", tei);
 		}
-		sub->subchannel = __pri_new_tei(-1, ctrl->localtype, ctrl->switchtype, ctrl, NULL, NULL, NULL, tei, 1);
-		if (!sub->subchannel) {
-			pri_error(ctrl, "Unable to allocate D-channel for new TEI %d\n", tei);
+		sub->next = pri_link_new(ctrl, Q921_SAPI_CALL_CTRL, tei);
+		if (!sub->next) {
+			pri_error(ctrl, "Unable to allocate layer 2 link for new TEI %d\n", tei);
 			return NULL;
 		}
-		q921_setstate(sub->subchannel, Q921_TEI_ASSIGNED);
+		q921_setstate(sub->next, Q921_TEI_ASSIGNED);
 		q921_send_tei(ctrl, Q921_TEI_IDENTITY_ASSIGNED, ri, tei, 1);
 		break;
 	case Q921_TEI_IDENTITY_ASSIGNED:
 		if (!BRI_TE_PTMP(ctrl))
 			return NULL;
 
-		/* Assuming we're operating on the sub here */
-		link = ctrl->subchannel;
+		/* Assuming we're operating on the specific TEI link here */
+		link = ctrl->link.next;
 		
-		switch (link->q921_state) {
+		switch (link->state) {
 		case Q921_ASSIGN_AWAITING_TEI:
 		case Q921_ESTABLISH_AWAITING_TEI:
 			break;
@@ -1269,7 +1272,7 @@ static pri_event *q921_receive_MDL(struct pri *ctrl, q921_u *h, int len)
 			pri_message(ctrl, "Got assigned TEI %d\n", tei);
 		}
 
-		switch (link->q921_state) {
+		switch (link->state) {
 		case Q921_ASSIGN_AWAITING_TEI:
 			q921_setstate(link, Q921_TEI_ASSIGNED);
 			ctrl->ev.gen.e = PRI_EVENT_DCHAN_UP;
@@ -1277,7 +1280,7 @@ static pri_event *q921_receive_MDL(struct pri *ctrl, q921_u *h, int len)
 			break;
 		case Q921_ESTABLISH_AWAITING_TEI:
 			q921_establish_data_link(link);
-			link->l3initiated = 1;
+			link->l3_initiated = 1;
 			q921_setstate(link, Q921_AWAITING_ESTABLISHMENT);
 			ctrl->ev.gen.e = PRI_EVENT_DCHAN_UP;
 			res = &ctrl->ev;
@@ -1290,10 +1293,10 @@ static pri_event *q921_receive_MDL(struct pri *ctrl, q921_u *h, int len)
 		if (!BRI_TE_PTMP(ctrl))
 			return NULL;
 
-		/* Assuming we're operating on the sub here */
-		link = ctrl->subchannel;
+		/* Assuming we're operating on the specific TEI link here */
+		link = ctrl->link.next;
 
-		if (link->q921_state < Q921_TEI_ASSIGNED) {
+		if (link->state < Q921_TEI_ASSIGNED) {
 			/* We do not have a TEI. */
 			return NULL;
 		}
@@ -1307,10 +1310,10 @@ static pri_event *q921_receive_MDL(struct pri *ctrl, q921_u *h, int len)
 		if (!BRI_TE_PTMP(ctrl))
 			return NULL;
 
-		/* Assuming we're operating on the sub here */
-		link = ctrl->subchannel;
+		/* Assuming we're operating on the specific TEI link here */
+		link = ctrl->link.next;
 
-		if (link->q921_state < Q921_TEI_ASSIGNED) {
+		if (link->state < Q921_TEI_ASSIGNED) {
 			/* We do not have a TEI. */
 			return NULL;
 		}
@@ -1337,7 +1340,7 @@ static int is_command(struct pri *ctrl, q921_h *h)
 	return command;
 }
 
-static void q921_clear_exception_conditions(struct pri *link)
+static void q921_clear_exception_conditions(struct q921_link *link)
 {
 	link->own_rx_busy = 0;
 	link->peer_rx_busy = 0;
@@ -1345,15 +1348,15 @@ static void q921_clear_exception_conditions(struct pri *link)
 	link->acknowledge_pending = 0;
 }
 
-static pri_event *q921_sabme_rx(struct pri *link, q921_h *h)
+static pri_event *q921_sabme_rx(struct q921_link *link, q921_h *h)
 {
 	pri_event *res = NULL;
 	struct pri *ctrl;
 	enum Q931_DL_EVENT delay_q931_dl_event;
 
-	ctrl = PRI_MASTER(link);
+	ctrl = link->ctrl;
 
-	switch (link->q921_state) {
+	switch (link->state) {
 	case Q921_TIMER_RECOVERY:
 		/* Timer recovery state handling is same as multiframe established */
 	case Q921_MULTI_FRAME_ESTABLISHED:
@@ -1402,25 +1405,25 @@ static pri_event *q921_sabme_rx(struct pri *link, q921_h *h)
 		break;
 	default:
 		pri_error(ctrl, "Cannot handle SABME in state %d(%s)\n",
-			link->q921_state, q921_state2str(link->q921_state));
+			link->state, q921_state2str(link->state));
 		break;
 	}
 
 	return res;
 }
 
-static pri_event *q921_disc_rx(struct pri *link, q921_h *h)
+static pri_event *q921_disc_rx(struct q921_link *link, q921_h *h)
 {
 	pri_event *res = NULL;
 	struct pri *ctrl;
 
-	ctrl = PRI_MASTER(link);
+	ctrl = link->ctrl;
 
 	if (ctrl->debug & PRI_DEBUG_Q921_STATE) {
 		pri_message(ctrl, "TEI=%d Got DISC\n", link->tei);
 	}
 
-	switch (link->q921_state) {
+	switch (link->state) {
 	case Q921_TEI_ASSIGNED:
 	case Q921_AWAITING_ESTABLISHMENT:
 		q921_send_dm(link, h->u.p_f);
@@ -1435,32 +1438,32 @@ static pri_event *q921_disc_rx(struct pri *link, q921_h *h)
 		/* DL-RELEASE indication */
 		q931_dl_event(link, Q931_DL_EVENT_DL_RELEASE_IND);
 		stop_t200(link);
-		if (link->q921_state == Q921_MULTI_FRAME_ESTABLISHED)
+		if (link->state == Q921_MULTI_FRAME_ESTABLISHED)
 			stop_t203(link);
 		q921_setstate(link, Q921_TEI_ASSIGNED);
 		q921_restart_ptp_link_if_needed(link);
 		break;
 	default:
 		pri_error(ctrl, "Don't know what to do with DISC in state %d(%s)\n",
-			link->q921_state, q921_state2str(link->q921_state));
+			link->state, q921_state2str(link->state));
 		break;
 	}
 
 	return res;
 }
 
-static void q921_mdl_remove(struct pri *link)
+static void q921_mdl_remove(struct q921_link *link)
 {
 	int mdl_free_me;
 	struct pri *ctrl;
 
-	ctrl = PRI_MASTER(link);
+	ctrl = link->ctrl;
 
 	if (ctrl->debug & PRI_DEBUG_Q921_STATE) {
 		pri_message(ctrl, "MDL-REMOVE: Removing TEI %d\n", link->tei);
 	}
 	if (BRI_NT_PTMP(ctrl)) {
-		if (link == ctrl) {
+		if (link == &ctrl->link) {
 			pri_error(ctrl, "Bad bad bad!  Cannot MDL-REMOVE master\n");
 			return;
 		}
@@ -1469,7 +1472,7 @@ static void q921_mdl_remove(struct pri *link)
 		mdl_free_me = 0;
 	}
 
-	switch (link->q921_state) {
+	switch (link->state) {
 	case Q921_TEI_ASSIGNED:
 		/* XXX: deviation! Since we don't have a UI queue, we just discard our I-queue */
 		q921_discard_iqueue(link);
@@ -1506,7 +1509,7 @@ static void q921_mdl_remove(struct pri *link)
 		break;
 	default:
 		pri_error(ctrl, "MDL-REMOVE when in state %d(%s)\n",
-			link->q921_state, q921_state2str(link->q921_state));
+			link->state, q921_state2str(link->state));
 		return;
 	}
 
@@ -1521,7 +1524,7 @@ static void q921_mdl_remove(struct pri *link)
 	link->mdl_free_me = mdl_free_me;
 }
 
-static int q921_mdl_handle_network_error(struct pri *link, char error)
+static int q921_mdl_handle_network_error(struct q921_link *link, char error)
 {
 	int handled = 0;
 	struct pri *ctrl;
@@ -1543,7 +1546,7 @@ static int q921_mdl_handle_network_error(struct pri *link, char error)
 	case 'K':
 		break;
 	default:
-		ctrl = PRI_MASTER(link);
+		ctrl = link->ctrl;
 		pri_error(ctrl, "Network MDL can't handle error of type %c\n", error);
 		break;
 	}
@@ -1551,7 +1554,7 @@ static int q921_mdl_handle_network_error(struct pri *link, char error)
 	return handled;
 }
 
-static int q921_mdl_handle_cpe_error(struct pri *link, char error)
+static int q921_mdl_handle_cpe_error(struct q921_link *link, char error)
 {
 	int handled = 0;
 	struct pri *ctrl;
@@ -1573,7 +1576,7 @@ static int q921_mdl_handle_cpe_error(struct pri *link, char error)
 	case 'K':
 		break;
 	default:
-		ctrl = PRI_MASTER(link);
+		ctrl = link->ctrl;
 		pri_error(ctrl, "CPE MDL can't handle error of type %c\n", error);
 		break;
 	}
@@ -1581,12 +1584,12 @@ static int q921_mdl_handle_cpe_error(struct pri *link, char error)
 	return handled;
 }
 
-static int q921_mdl_handle_ptp_error(struct pri *link, char error)
+static int q921_mdl_handle_ptp_error(struct q921_link *link, char error)
 {
 	int handled = 0;
 	struct pri *ctrl;
 
-	ctrl = PRI_MASTER(link);
+	ctrl = link->ctrl;
 
 	/* This is where we act a bit like L3 instead of L2, since we've got an L3 that depends on us
 	 * keeping L2 automatically alive and happy for point to point links */
@@ -1600,7 +1603,7 @@ static int q921_mdl_handle_ptp_error(struct pri *link, char error)
 		q921_discard_iqueue(link);
 		q921_establish_data_link(link);
 		q921_setstate(link, Q921_AWAITING_ESTABLISHMENT);
-		link->l3initiated = 1;
+		link->l3_initiated = 1;
 
 		ctrl->schedev = 1;
 		ctrl->ev.gen.e = PRI_EVENT_DCHAN_DOWN;
@@ -1626,21 +1629,21 @@ static int q921_mdl_handle_ptp_error(struct pri *link, char error)
 	return handled;
 }
 
-static void q921_restart_ptp_link_if_needed(struct pri *link)
+static void q921_restart_ptp_link_if_needed(struct q921_link *link)
 {
 	struct pri *ctrl;
 
-	ctrl = PRI_MASTER(link);
+	ctrl = link->ctrl;
 	if (PTP_MODE(ctrl)) {
-		q921_mdl_error(ctrl, 'Z');
+		q921_mdl_error(&ctrl->link, 'Z');
 	}
 }
 
-static void q921_mdl_handle_error(struct pri *link, char error, int errored_state)
+static void q921_mdl_handle_error(struct q921_link *link, char error, int errored_state)
 {
 	struct pri *ctrl;
 
-	ctrl = PRI_MASTER(link);
+	ctrl = link->ctrl;
 
 	if (PTP_MODE(ctrl)) {
 		q921_mdl_handle_ptp_error(link, error);
@@ -1655,7 +1658,7 @@ static void q921_mdl_handle_error(struct pri *link, char error, int errored_stat
 
 static void q921_mdl_handle_error_callback(void *vlink)
 {
-	struct pri *link = vlink;
+	struct q921_link *link = vlink;
 
 	q921_mdl_handle_error(link, link->mdl_error, link->mdl_error_state);
 
@@ -1664,22 +1667,19 @@ static void q921_mdl_handle_error_callback(void *vlink)
 
 	if (link->mdl_free_me) {
 		struct pri *ctrl;
-		struct pri *freep = NULL, *prev, *cur;
+		struct q921_link *freep;
+		struct q921_link *prev;
 
-		ctrl = PRI_MASTER(link);
-		prev = ctrl;
-		cur = ctrl->subchannel;
+		ctrl = link->ctrl;
 
-		while (cur) {
-			if (cur == link) {
-				prev->subchannel = cur->subchannel;
-				freep = cur;
+		freep = NULL;
+		for (prev = &ctrl->link; prev->next; prev = prev->next) {
+			if (prev->next == link) {
+				prev->next = link->next;
+				freep = link;
 				break;
 			}
-			prev = cur;
-			cur = cur->subchannel;
 		}
-
 		if (freep == NULL) {
 			pri_error(ctrl, "Huh!? no match found in list for TEI %d\n", -link->tei);
 			return;
@@ -1689,16 +1689,16 @@ static void q921_mdl_handle_error_callback(void *vlink)
 			pri_message(ctrl, "Freeing TEI of %d\n", -freep->tei);
 		}
 
-		__pri_free_tei(freep);
+		pri_link_destroy(freep);
 	}
 }
 
-static void q921_mdl_error(struct pri *link, char error)
+static void q921_mdl_error(struct q921_link *link, char error)
 {
 	int is_debug_q921_state;
 	struct pri *ctrl;
 
-	ctrl = PRI_MASTER(link);
+	ctrl = link->ctrl;
 
 	/* Log the MDL-ERROR event when detected. */
 	is_debug_q921_state = (ctrl->debug & PRI_DEBUG_Q921_STATE);
@@ -1706,20 +1706,20 @@ static void q921_mdl_error(struct pri *link, char error)
 	case 'A':
 		pri_message(ctrl,
 			"TEI=%d MDL-ERROR (A): Got supervisory frame with F=1 in state %d(%s)\n",
-			link->tei, link->q921_state, q921_state2str(link->q921_state));
+			link->tei, link->state, q921_state2str(link->state));
 		break;
 	case 'B':
 	case 'E':
 		pri_message(ctrl, "TEI=%d MDL-ERROR (%c): DM (F=%c) in state %d(%s)\n",
 			link->tei, error, (error == 'B') ? '1' : '0',
-			link->q921_state, q921_state2str(link->q921_state));
+			link->state, q921_state2str(link->state));
 		break;
 	case 'C':
 	case 'D':
 		if (is_debug_q921_state || PTP_MODE(ctrl)) {
 			pri_message(ctrl, "TEI=%d MDL-ERROR (%c): UA (F=%c) in state %d(%s)\n",
 				link->tei, error, (error == 'C') ? '1' : '0',
-				link->q921_state, q921_state2str(link->q921_state));
+				link->state, q921_state2str(link->state));
 		}
 		break;
 	case 'F':
@@ -1738,7 +1738,7 @@ static void q921_mdl_error(struct pri *link, char error)
 			 * reasons 1-3 above.
 			 */
 			pri_message(ctrl, "TEI=%d MDL-ERROR (F): SABME in state %d(%s)\n",
-				link->tei, link->q921_state, q921_state2str(link->q921_state));
+				link->tei, link->state, q921_state2str(link->state));
 		}
 		break;
 	case 'G':
@@ -1746,7 +1746,7 @@ static void q921_mdl_error(struct pri *link, char error)
 		if (is_debug_q921_state) {
 			pri_message(ctrl,
 				"TEI=%d MDL-ERROR (G): T200 expired N200 times sending SABME in state %d(%s)\n",
-				link->tei, link->q921_state, q921_state2str(link->q921_state));
+				link->tei, link->state, q921_state2str(link->state));
 		}
 		break;
 	case 'H':
@@ -1754,7 +1754,7 @@ static void q921_mdl_error(struct pri *link, char error)
 		if (is_debug_q921_state) {
 			pri_message(ctrl,
 				"TEI=%d MDL-ERROR (H): T200 expired N200 times sending DISC in state %d(%s)\n",
-				link->tei, link->q921_state, q921_state2str(link->q921_state));
+				link->tei, link->state, q921_state2str(link->state));
 		}
 		break;
 	case 'I':
@@ -1762,13 +1762,13 @@ static void q921_mdl_error(struct pri *link, char error)
 		if (is_debug_q921_state) {
 			pri_message(ctrl,
 				"TEI=%d MDL-ERROR (I): T200 expired N200 times sending RR/RNR in state %d(%s)\n",
-				link->tei, link->q921_state, q921_state2str(link->q921_state));
+				link->tei, link->state, q921_state2str(link->state));
 		}
 		break;
 	case 'J':
 		/* N(R) not within ack window. */
 		pri_error(ctrl, "TEI=%d MDL-ERROR (J): N(R) error in state %d(%s)\n",
-			link->tei, link->q921_state, q921_state2str(link->q921_state));
+			link->tei, link->state, q921_state2str(link->state));
 		break;
 	case 'K':
 		/*
@@ -1776,19 +1776,19 @@ static void q921_mdl_error(struct pri *link, char error)
 		 * The other end does not like what we are doing at all for some reason.
 		 */
 		pri_error(ctrl, "TEI=%d MDL-ERROR (K): FRMR in state %d(%s)\n",
-			link->tei, link->q921_state, q921_state2str(link->q921_state));
+			link->tei, link->state, q921_state2str(link->state));
 		break;
 	case 'Z':
 		if (is_debug_q921_state) {
 			/* Fake MDL-ERROR to kick start PTP L2 link back up. */
 			pri_message(ctrl,
 				"TEI=%d MDL-ERROR (Z): Kick starting L2 link in state %d(%s)\n",
-				link->tei, link->q921_state, q921_state2str(link->q921_state));
+				link->tei, link->state, q921_state2str(link->state));
 		}
 		break;
 	default:
 		pri_message(ctrl, "TEI=%d MDL-ERROR (%c): in state %d(%s)\n",
-			link->tei, error, link->q921_state, q921_state2str(link->q921_state));
+			link->tei, error, link->state, q921_state2str(link->state));
 		break;
 	}
 
@@ -1800,23 +1800,23 @@ static void q921_mdl_error(struct pri *link, char error)
 		return;
 	}
 	link->mdl_error = error;
-	link->mdl_error_state = link->q921_state;
+	link->mdl_error_state = link->state;
 	link->mdl_timer = pri_schedule_event(ctrl, 0, q921_mdl_handle_error_callback, link);
 }
 
-static pri_event *q921_ua_rx(struct pri *link, q921_h *h)
+static pri_event *q921_ua_rx(struct q921_link *link, q921_h *h)
 {
 	struct pri *ctrl;
 	pri_event *res = NULL;
 	enum Q931_DL_EVENT delay_q931_dl_event;
 
-	ctrl = PRI_MASTER(link);
+	ctrl = link->ctrl;
 
 	if (ctrl->debug & PRI_DEBUG_Q921_STATE) {
 		pri_message(ctrl, "TEI=%d Got UA\n", link->tei);
 	}
 
-	switch (link->q921_state) {
+	switch (link->state) {
 	case Q921_TEI_ASSIGNED:
 	case Q921_MULTI_FRAME_ESTABLISHED:
 	case Q921_TIMER_RECOVERY:
@@ -1833,14 +1833,14 @@ static pri_event *q921_ua_rx(struct pri *link, q921_h *h)
 		}
 
 		delay_q931_dl_event = Q931_DL_EVENT_NONE;
-		if (!link->l3initiated) {
+		if (!link->l3_initiated) {
 			if (link->v_s != link->v_a) {
 				q921_discard_iqueue(link);
 				/* DL-ESTABLISH indication */
 				delay_q931_dl_event = Q931_DL_EVENT_DL_ESTABLISH_IND;
 			}
 		} else {
-			link->l3initiated = 0;
+			link->l3_initiated = 0;
 			/* DL-ESTABLISH confirm */
 			delay_q931_dl_event = Q931_DL_EVENT_DL_ESTABLISH_CONFIRM;
 		}
@@ -1873,20 +1873,20 @@ static pri_event *q921_ua_rx(struct pri *link, q921_h *h)
 		break;
 	default:
 		pri_error(ctrl, "Don't know what to do with UA in state %d(%s)\n",
-			link->q921_state, q921_state2str(link->q921_state));
+			link->state, q921_state2str(link->state));
 		break;
 	}
 
 	return res;
 }
 
-static void q921_enquiry_response(struct pri *link)
+static void q921_enquiry_response(struct q921_link *link)
 {
 	struct pri *ctrl;
 
 	if (link->own_rx_busy) {
 		/* XXX : TODO later sometime */
-		ctrl = PRI_MASTER(link);
+		ctrl = link->ctrl;
 		pri_error(ctrl, "Implement me %s: own_rx_busy\n", __FUNCTION__);
 		//q921_rnr(link);
 	} else {
@@ -1896,22 +1896,22 @@ static void q921_enquiry_response(struct pri *link)
 	link->acknowledge_pending = 0;
 }
 
-static void n_r_error_recovery(struct pri *link)
+static void n_r_error_recovery(struct q921_link *link)
 {
 	q921_mdl_error(link, 'J');
 
 	q921_establish_data_link(link);
 
-	link->l3initiated = 0;
+	link->l3_initiated = 0;
 }
 
-static void update_v_a(struct pri *link, int n_r)
+static void update_v_a(struct q921_link *link, int n_r)
 {
 	int idealcnt = 0, realcnt = 0;
 	int x;
 	struct pri *ctrl;
 
-	ctrl = PRI_MASTER(link);
+	ctrl = link->ctrl;
 
 	/* Cancel each packet as necessary */
 	if (ctrl->debug & PRI_DEBUG_Q921_DUMP)
@@ -1928,7 +1928,7 @@ static void update_v_a(struct pri *link, int n_r)
 	link->v_a = n_r;
 }
 
-static int n_r_is_valid(struct pri *link, int n_r)
+static int n_r_is_valid(struct q921_link *link, int n_r)
 {
 	int x;
 
@@ -1942,13 +1942,13 @@ static int n_r_is_valid(struct pri *link, int n_r)
 	}
 }
 
-static int q921_invoke_retransmission(struct pri *link, int n_r);
+static int q921_invoke_retransmission(struct q921_link *link, int n_r);
 
-static pri_event *timer_recovery_rr_rej_rx(struct pri *link, q921_h *h)
+static pri_event *timer_recovery_rr_rej_rx(struct q921_link *link, q921_h *h)
 {
 	struct pri *ctrl;
 
-	ctrl = PRI_MASTER(link);
+	ctrl = link->ctrl;
 
 	/* Figure B.7/Q.921 Page 74 */
 	link->peer_rx_busy = 0;
@@ -1989,12 +1989,12 @@ n_r_error_out:
 	return NULL;
 }
 
-static pri_event *q921_rr_rx(struct pri *link, q921_h *h)
+static pri_event *q921_rr_rx(struct q921_link *link, q921_h *h)
 {
 	pri_event *res = NULL;
 	struct pri *ctrl;
 
-	ctrl = PRI_MASTER(link);
+	ctrl = link->ctrl;
 
 #if 0	/* Don't flood debug trace with RR if not really looking at Q.921 layer. */
 	if (ctrl->debug & PRI_DEBUG_Q921_STATE) {
@@ -2002,7 +2002,7 @@ static pri_event *q921_rr_rx(struct pri *link, q921_h *h)
 	}
 #endif
 
-	switch (link->q921_state) {
+	switch (link->state) {
 	case Q921_TIMER_RECOVERY:
 		res = timer_recovery_rr_rej_rx(link, h);
 		break;
@@ -2048,14 +2048,14 @@ static pri_event *q921_rr_rx(struct pri *link, q921_h *h)
 		break;
 	default:
 		pri_error(ctrl, "Don't know what to do with RR in state %d(%s)\n",
-			link->q921_state, q921_state2str(link->q921_state));
+			link->state, q921_state2str(link->state));
 		break;
 	}
 
 	return res;
 }
 
-static int q921_invoke_retransmission(struct pri *link, int n_r)
+static int q921_invoke_retransmission(struct q921_link *link, int n_r)
 {
 	int frames_txd = 0;
 	int frames_supposed_to_tx = 0;
@@ -2063,10 +2063,10 @@ static int q921_invoke_retransmission(struct pri *link, int n_r)
 	unsigned int local_v_s = link->v_s;
 	struct pri *ctrl;
 
-	ctrl = PRI_MASTER(link);
+	ctrl = link->ctrl;
 
 	/* All acked frames should already have been removed from the queue. */
-	for (f = link->txqueue; f && f->transmitted; f = f->next) {
+	for (f = link->tx_queue; f && f->transmitted; f = f->next) {
 		if (ctrl->debug & PRI_DEBUG_Q921_STATE) {
 			pri_message(ctrl, "TEI=%d Retransmitting frame N(S)=%d now!\n",
 				link->tei, f->h.n_s);
@@ -2090,18 +2090,18 @@ static int q921_invoke_retransmission(struct pri *link, int n_r)
 	return frames_txd;
 }
 
-static pri_event *q921_rej_rx(struct pri *link, q921_h *h)
+static pri_event *q921_rej_rx(struct q921_link *link, q921_h *h)
 {
 	pri_event *res = NULL;
 	struct pri *ctrl;
 
-	ctrl = PRI_MASTER(link);
+	ctrl = link->ctrl;
 
 	if (ctrl->debug & PRI_DEBUG_Q921_STATE) {
 		pri_message(ctrl, "TEI=%d Got REJ N(R)=%d\n", link->tei, h->s.n_r);
 	}
 
-	switch (link->q921_state) {
+	switch (link->state) {
 	case Q921_TIMER_RECOVERY:
 		res = timer_recovery_rr_rej_rx(link, h);
 		break;
@@ -2140,30 +2140,30 @@ static pri_event *q921_rej_rx(struct pri *link, q921_h *h)
 		break;
 	default:
 		pri_error(ctrl, "Don't know what to do with REJ in state %d(%s)\n",
-			link->q921_state, q921_state2str(link->q921_state));
+			link->state, q921_state2str(link->state));
 		break;
 	}
 
 	return res;
 }
 
-static pri_event *q921_frmr_rx(struct pri *link, q921_h *h)
+static pri_event *q921_frmr_rx(struct q921_link *link, q921_h *h)
 {
 	pri_event *res = NULL;
 	struct pri *ctrl;
 
-	ctrl = PRI_MASTER(link);
+	ctrl = link->ctrl;
 
 	if (ctrl->debug & PRI_DEBUG_Q921_STATE) {
 		pri_message(ctrl, "TEI=%d Got FRMR\n", link->tei);
 	}
 
-	switch (link->q921_state) {
+	switch (link->state) {
 	case Q921_TIMER_RECOVERY:
 	case Q921_MULTI_FRAME_ESTABLISHED:
 		q921_mdl_error(link, 'K');
 		q921_establish_data_link(link);
-		link->l3initiated = 0;
+		link->l3_initiated = 0;
 		q921_setstate(link, Q921_AWAITING_ESTABLISHMENT);
 		break;
 	case Q921_TEI_ASSIGNED:
@@ -2179,23 +2179,23 @@ static pri_event *q921_frmr_rx(struct pri *link, q921_h *h)
 		break;
 	default:
 		pri_error(ctrl, "Don't know what to do with FRMR in state %d(%s)\n",
-			link->q921_state, q921_state2str(link->q921_state));
+			link->state, q921_state2str(link->state));
 		break;
 	}
 
 	return res;
 }
 
-static pri_event *q921_iframe_rx(struct pri *link, q921_h *h, int len)
+static pri_event *q921_iframe_rx(struct q921_link *link, q921_h *h, int len)
 {
 	struct pri *ctrl;
 	pri_event *eres = NULL;
 	int res = 0;
 	int delay_q931_receive;
 
-	ctrl = PRI_MASTER(link);
+	ctrl = link->ctrl;
 
-	switch (link->q921_state) {
+	switch (link->state) {
 	case Q921_TIMER_RECOVERY:
 	case Q921_MULTI_FRAME_ESTABLISHED:
 		delay_q931_receive = 0;
@@ -2240,7 +2240,7 @@ static pri_event *q921_iframe_rx(struct pri *link, q921_h *h, int len)
 			n_r_error_recovery(link);
 			q921_setstate(link, Q921_AWAITING_ESTABLISHMENT);
 		} else {
-			if (link->q921_state == Q921_TIMER_RECOVERY) {
+			if (link->state == Q921_TIMER_RECOVERY) {
 				update_v_a(link, h->i.n_r);
 			} else {
 				if (link->peer_rx_busy) {
@@ -2277,31 +2277,31 @@ static pri_event *q921_iframe_rx(struct pri *link, q921_h *h, int len)
 		break;
 	default:
 		pri_error(ctrl, "Don't know what to do with an I-frame in state %d(%s)\n",
-			link->q921_state, q921_state2str(link->q921_state));
+			link->state, q921_state2str(link->state));
 		break;
 	}
 
 	return eres;
 }
 
-static pri_event *q921_dm_rx(struct pri *link, q921_h *h)
+static pri_event *q921_dm_rx(struct q921_link *link, q921_h *h)
 {
 	pri_event *res = NULL;
 	struct pri *ctrl;
 
-	ctrl = PRI_MASTER(link);
+	ctrl = link->ctrl;
 
 	if (ctrl->debug & PRI_DEBUG_Q921_STATE) {
 		pri_message(ctrl, "TEI=%d Got DM\n", link->tei);
 	}
 
-	switch (link->q921_state) {
+	switch (link->state) {
 	case Q921_TEI_ASSIGNED:
 		if (h->u.p_f)
 			break;
 		/* else */
 		q921_establish_data_link(link);
-		link->l3initiated = 1;
+		link->l3_initiated = 1;
 		q921_setstate(link, Q921_AWAITING_ESTABLISHMENT);
 		break;
 	case Q921_AWAITING_ESTABLISHMENT:
@@ -2331,7 +2331,7 @@ static pri_event *q921_dm_rx(struct pri *link, q921_h *h)
 
 		q921_mdl_error(link, 'E');
 		q921_establish_data_link(link);
-		link->l3initiated = 0;
+		link->l3_initiated = 0;
 		q921_setstate(link, Q921_AWAITING_ESTABLISHMENT);
 		break;
 	case Q921_TIMER_RECOVERY:
@@ -2341,30 +2341,30 @@ static pri_event *q921_dm_rx(struct pri *link, q921_h *h)
 			q921_mdl_error(link, 'E');
 		}
 		q921_establish_data_link(link);
-		link->l3initiated = 0;
+		link->l3_initiated = 0;
 		q921_setstate(link, Q921_AWAITING_ESTABLISHMENT);
 		break;
 	default:
 		pri_error(ctrl, "Don't know what to do with DM frame in state %d(%s)\n",
-			link->q921_state, q921_state2str(link->q921_state));
+			link->state, q921_state2str(link->state));
 		break;
 	}
 
 	return res;
 }
 
-static pri_event *q921_rnr_rx(struct pri *link, q921_h *h)
+static pri_event *q921_rnr_rx(struct q921_link *link, q921_h *h)
 {
 	pri_event *res = NULL;
 	struct pri *ctrl;
 
-	ctrl = PRI_MASTER(link);
+	ctrl = link->ctrl;
 
 	if (ctrl->debug & PRI_DEBUG_Q921_STATE) {
 		pri_message(ctrl, "TEI=%d Got RNR N(R)=%d\n", link->tei, h->s.n_r);
 	}
 
-	switch (link->q921_state) {
+	switch (link->state) {
 	case Q921_MULTI_FRAME_ESTABLISHED:
 		link->peer_rx_busy = 1;
 		if (!is_command(ctrl, h)) {
@@ -2436,14 +2436,14 @@ static pri_event *q921_rnr_rx(struct pri *link, q921_h *h)
 		break;
 	default:
 		pri_error(ctrl, "Don't know what to do with RNR in state %d(%s)\n",
-			link->q921_state, q921_state2str(link->q921_state));
+			link->state, q921_state2str(link->state));
 		break;
 	}
 
 	return res;
 }
 
-static void q921_acknowledge_pending_check(struct pri *link)
+static void q921_acknowledge_pending_check(struct q921_link *link)
 {
 	if (link->acknowledge_pending) {
 		link->acknowledge_pending = 0;
@@ -2451,9 +2451,9 @@ static void q921_acknowledge_pending_check(struct pri *link)
 	}
 }
 
-static void q921_statemachine_check(struct pri *link)
+static void q921_statemachine_check(struct q921_link *link)
 {
-	switch (link->q921_state) {
+	switch (link->state) {
 	case Q921_MULTI_FRAME_ESTABLISHED:
 		q921_send_queued_iframes(link);
 		q921_acknowledge_pending_check(link);
@@ -2466,13 +2466,13 @@ static void q921_statemachine_check(struct pri *link)
 	}
 }
 
-static pri_event *__q921_receive_qualified(struct pri *link, q921_h *h, int len)
+static pri_event *__q921_receive_qualified(struct q921_link *link, q921_h *h, int len)
 {
 	int res;
 	pri_event *ev = NULL;
 	struct pri *ctrl;
 
-	ctrl = PRI_MASTER(link);
+	ctrl = link->ctrl;
 
 	switch(h->h.data[0] & Q921_FRAMETYPE_MASK) {
 	case 0:
@@ -2580,7 +2580,7 @@ static pri_event *q921_handle_unmatched_frame(struct pri *ctrl, q921_h *h, int l
 	if (BRI_NT_PTMP(ctrl)) {
 		if (ctrl->debug & PRI_DEBUG_Q921_STATE) {
 			pri_message(ctrl,
-				"Could not find candidate subchannel for received frame with SAPI/TEI of %d/%d.\n",
+				"Could not find a layer 2 link for received frame with SAPI/TEI of %d/%d.\n",
 				h->h.sapi, h->h.tei);
 			pri_message(ctrl, "Sending TEI release, in order to re-establish TEI state\n");
 		}
@@ -2597,7 +2597,7 @@ static pri_event *q921_handle_unmatched_frame(struct pri *ctrl, q921_h *h, int l
 static pri_event *__q921_receive(struct pri *ctrl, q921_h *h, int len)
 {
 	pri_event *ev = NULL;
-	struct pri *link;
+	struct q921_link *link;
 
 	/* Discard FCS */
 	len -= 2;
@@ -2621,14 +2621,15 @@ static pri_event *__q921_receive(struct pri *ctrl, q921_h *h, int len)
 	}
 
 	if (BRI_TE_PTMP(ctrl)) {
-		link = ctrl->subchannel;
+		/* We're operating on the specific TEI link */
+		link = ctrl->link.next;
 		if (h->h.sapi == link->sapi
-			&& ((link->q921_state >= Q921_TEI_ASSIGNED
+			&& ((link->state >= Q921_TEI_ASSIGNED
 				&& h->h.tei == link->tei)
 				|| h->h.tei == Q921_TEI_GROUP)) {
 			ev = __q921_receive_qualified(link, h, len);
 		}
-		/* Only support reception on our single subchannel */
+		/* Only support reception on our specific TEI link */
 	} else if (BRI_NT_PTMP(ctrl)) {
 		link = pri_find_tei(ctrl, h->h.sapi, h->h.tei);
 		if (link) {
@@ -2636,8 +2637,9 @@ static pri_event *__q921_receive(struct pri *ctrl, q921_h *h, int len)
 		} else {
 			ev = q921_handle_unmatched_frame(ctrl, h, len);
 		}
-	} else if (PTP_MODE(ctrl) && (h->h.sapi == ctrl->sapi) && (h->h.tei == ctrl->tei)) {
-		ev = __q921_receive_qualified(ctrl, h, len);
+	} else if (PTP_MODE(ctrl)
+			&& h->h.sapi == ctrl->link.sapi && h->h.tei == ctrl->link.tei) {
+		ev = __q921_receive_qualified(&ctrl->link, h, len);
 	} else {
 		ev = NULL;
 	}
@@ -2659,7 +2661,7 @@ pri_event *q921_receive(struct pri *ctrl, q921_h *h, int len)
 	return e;
 }
 
-static void q921_establish_data_link(struct pri *link)
+static void q921_establish_data_link(struct q921_link *link)
 {
 	q921_clear_exception_conditions(link);
 	link->RC = 0;
@@ -2676,11 +2678,11 @@ static void nt_ptmp_dchannel_up(void *vpri)
 	ctrl->ev.gen.e = PRI_EVENT_DCHAN_UP;
 }
 
-void q921_start(struct pri *link)
+void q921_start(struct q921_link *link)
 {
 	struct pri *ctrl;
 
-	ctrl = PRI_MASTER(link);
+	ctrl = link->ctrl;
 	if (PTMP_MODE(ctrl)) {
 		if (TE_MODE(ctrl)) {
 			q921_setstate(link, Q921_ASSIGN_AWAITING_TEI);
@@ -2692,7 +2694,7 @@ void q921_start(struct pri *link)
 	} else {
 		/* PTP mode, no need for TEI management junk */
 		q921_establish_data_link(link);
-		link->l3initiated = 1;
+		link->l3_initiated = 1;
 		q921_setstate(link, Q921_AWAITING_ESTABLISHMENT);
 	}
 }
diff --git a/q931.c b/q931.c
index 34fafeb..764dfd8 100644
--- a/q931.c
+++ b/q931.c
@@ -334,7 +334,7 @@ static int q931_encode_channel(const q931_call *call)
 int q931_is_call_valid(struct pri *ctrl, struct q931_call *call)
 {
 	struct q931_call *cur;
-	struct pri *link;
+	struct q921_link *link;
 	int idx;
 
 	if (!call) {
@@ -347,11 +347,7 @@ int q931_is_call_valid(struct pri *ctrl, struct q931_call *call)
 			/* Definitely a bad call pointer. */
 			return 0;
 		}
-		/* Find the master - He has the call pool */
-		ctrl = PRI_MASTER(call->pri);
-	} else {
-		/* Find the master - He has the call pool */
-		ctrl = PRI_MASTER(ctrl);
+		ctrl = call->pri;
 	}
 
 	/* Check real call records. */
@@ -372,7 +368,7 @@ int q931_is_call_valid(struct pri *ctrl, struct q931_call *call)
 	}
 
 	/* Check dummy call records. */
-	for (link = ctrl; link; link = link->subchannel) {
+	for (link = &ctrl->link; link; link = link->next) {
 		if (link->dummy_call == call) {
 			/* Found it. */
 			return 1;
@@ -1612,7 +1608,7 @@ static int transmit_bearer_capability(int full_ie, struct pri *ctrl, q931_call *
 	if(order > 1)
 		return 0;
 
-	if (ctrl->subchannel && !ctrl->bri) {
+	if (ctrl->link.next && !ctrl->bri) {
 		/* Bearer capability is *hard coded* in GR-303 */
 		ie->data[0] = 0x88;
 		ie->data[1] = 0x90;
@@ -2744,7 +2740,7 @@ static int transmit_progress_indicator(int full_ie, struct pri *ctrl, q931_call
 {
 	int code, mask;
 	/* Can't send progress indicator on GR-303 -- EVER! */
-	if (ctrl->subchannel && !ctrl->bri)
+	if (ctrl->link.next && !ctrl->bri)
 		return 0;
 	if (call->progressmask > 0) {
 		if (call->progressmask & (mask = PRI_PROG_CALL_NOT_E2E_ISDN))
@@ -3786,7 +3782,7 @@ static inline void q931_dumpie(struct pri *ctrl, int codeset, q931_ie *ie, char
  *
  * \return Nothing
  */
-void q931_init_call_record(struct pri *link, struct q931_call *call, int cr)
+void q931_init_call_record(struct q921_link *link, struct q931_call *call, int cr)
 {
 	struct pri *ctrl;
 
@@ -3825,14 +3821,14 @@ void q931_init_call_record(struct pri *link, struct q931_call *call, int cr)
 	q931_party_redirecting_init(&call->redirecting);
 
 	/* The call is now attached to whoever called us */
-	ctrl = PRI_MASTER(link);
+	ctrl = link->ctrl;
 	call->pri = ctrl;
 	if (cr == Q931_DUMMY_CALL_REFERENCE) {
 		/* Dummy calls are always for the given link. */
 		call->link = link;
 	} else if (BRI_TE_PTMP(ctrl)) {
 		/* Always uses the specific TEI link. */
-		call->link = ctrl->subchannel;
+		call->link = ctrl->link.next;
 	} else {
 		call->link = link;
 	}
@@ -3848,14 +3844,13 @@ void q931_init_call_record(struct pri *link, struct q931_call *call, int cr)
  * \retval record on success.
  * \retval NULL on error.
  */
-static struct q931_call *q931_create_call_record(struct pri *link, int cr)
+static struct q931_call *q931_create_call_record(struct q921_link *link, int cr)
 {
 	struct q931_call *call;
 	struct q931_call *prev;
 	struct pri *ctrl;
 
-	/* Find the master - He has the call pool */
-	ctrl = PRI_MASTER(link);
+	ctrl = link->ctrl;
 
 	if (ctrl->debug & PRI_DEBUG_Q931_STATE) {
 		pri_message(ctrl, "-- Making new call for cref %d\n", cr);
@@ -3893,7 +3888,7 @@ static struct q931_call *q931_create_call_record(struct pri *link, int cr)
  * \retval call if found.
  * \retval NULL if not found.
  */
-static struct q931_call *q931_find_call(struct pri *link, int cr)
+static struct q931_call *q931_find_call(struct q921_link *link, int cr)
 {
 	struct q931_call *cur;
 	struct pri *ctrl;
@@ -3902,8 +3897,7 @@ static struct q931_call *q931_find_call(struct pri *link, int cr)
 		return link->dummy_call;
 	}
 
-	/* Find the master - He has the call pool */
-	ctrl = PRI_MASTER(link);
+	ctrl = link->ctrl;
 
 	if (BRI_NT_PTMP(ctrl) && !(cr & Q931_CALL_REFERENCE_FLAG)) {
 		if (link->tei == Q921_TEI_GROUP) {
@@ -3925,9 +3919,7 @@ static struct q931_call *q931_find_call(struct pri *link, int cr)
 				/* Found existing call. */
 				switch (ctrl->switchtype) {
 				case PRI_SWITCH_GR303_EOC:
-				case PRI_SWITCH_GR303_EOC_PATH:
 				case PRI_SWITCH_GR303_TMC:
-				case PRI_SWITCH_GR303_TMC_SWITCHING:
 					break;
 				default:
 					if (!ctrl->bri) {
@@ -3944,7 +3936,7 @@ static struct q931_call *q931_find_call(struct pri *link, int cr)
 	return cur;
 }
 
-static struct q931_call *q931_getcall(struct pri *link, int cr)
+static struct q931_call *q931_getcall(struct q921_link *link, int cr)
 {
 	struct q931_call *cur;
 	struct pri *ctrl;
@@ -3957,7 +3949,7 @@ static struct q931_call *q931_getcall(struct pri *link, int cr)
 		/* Do not create new dummy call records. */
 		return NULL;
 	}
-	ctrl = PRI_MASTER(link);
+	ctrl = link->ctrl;
 	if (link->tei == Q921_TEI_GROUP
 		&& BRI_NT_PTMP(ctrl)) {
 		/* Do not create NT PTMP broadcast call records here. */
@@ -3981,13 +3973,10 @@ static struct q931_call *q931_getcall(struct pri *link, int cr)
 struct q931_call *q931_new_call(struct pri *ctrl)
 {
 	struct q931_call *cur;
-	struct pri *link;
+	struct q921_link *link;
 	int first_cref;
 	int cref;
 
-	/* Find the master - He has the call pool */
-	ctrl = PRI_MASTER(ctrl);
-
 	/* Find a new call reference value. */
 	first_cref = ctrl->cref;
 	do {
@@ -4018,7 +4007,7 @@ struct q931_call *q931_new_call(struct pri *ctrl)
 		}
 	} while (cur);
 
-	link = ctrl;
+	link = &ctrl->link;
 	return q931_create_call_record(link, cref);
 }
 
@@ -4063,9 +4052,6 @@ void q931_destroycall(struct pri *ctrl, q931_call *c)
 		slave = NULL;
 	}
 
-	/* For destroying, make sure we are using the master span, since it maintains the call pool */
-	ctrl = PRI_MASTER(ctrl);
-
 	prev = NULL;
 	cur = *ctrl->callpool;
 	while (cur) {
@@ -4478,7 +4464,7 @@ static void init_header(struct pri *ctrl, q931_call *call, unsigned char *buf, q
 	} else if (!ctrl->bri) {
 		/* Two bytes of Call Reference. */
 		h->crlen = 2;
-		if (ctrl->subchannel) {
+		if (ctrl->link.next) {
 			/* On GR-303, Q931_CALL_REFERENCE_FLAG is always 0 */
 			crv = ((unsigned) call->cr) & ~Q931_CALL_REFERENCE_FLAG;
 		} else {
@@ -4503,11 +4489,11 @@ static void init_header(struct pri *ctrl, q931_call *call, unsigned char *buf, q
 	*mhb = mh;
 }
 
-static void q931_xmit(struct pri *link, q931_h *h, int len, int cr, int uiframe)
+static void q931_xmit(struct q921_link *link, q931_h *h, int len, int cr, int uiframe)
 {
 	struct pri *ctrl;
 
-	ctrl = PRI_MASTER(link);
+	ctrl = link->ctrl;
 #ifdef LIBPRI_COUNTERS
 	ctrl->q931_txcount++;
 #endif
@@ -4671,7 +4657,7 @@ int maintenance_service(struct pri *ctrl, int span, int channel, int changestatu
 	int pd = MAINTENANCE_PROTOCOL_DISCRIMINATOR_1;
 	int mt = ATT_SERVICE;
 
-	c = q931_getcall(ctrl, 0 | Q931_CALL_REFERENCE_FLAG);
+	c = q931_getcall(&ctrl->link, 0 | Q931_CALL_REFERENCE_FLAG);
 	if (!c) {
 		return -1;
 	}
@@ -5105,7 +5091,7 @@ int q931_connect(struct pri *ctrl, q931_call *c, int channel, int nonisdn)
 	/* Connect request timer */
 	pri_schedule_del(ctrl, c->retranstimer);
 	c->retranstimer = 0;
-	if ((c->ourcallstate == Q931_CALL_STATE_CONNECT_REQUEST) && (ctrl->bri || (!ctrl->subchannel)))
+	if ((c->ourcallstate == Q931_CALL_STATE_CONNECT_REQUEST) && (ctrl->bri || (!ctrl->link.next)))
 		c->retranstimer = pri_schedule_event(ctrl, ctrl->timers[PRI_TIMER_T313], pri_connect_timeout, c);
 
 	if (c->redirecting.state == Q931_REDIRECTING_STATE_PENDING_TX_DIV_LEG_3) {
@@ -5197,7 +5183,7 @@ int q931_restart(struct pri *ctrl, int channel)
 {
 	struct q931_call *c;
 
-	c = q931_getcall(ctrl, 0 | Q931_CALL_REFERENCE_FLAG);
+	c = q931_getcall(&ctrl->link, 0 | Q931_CALL_REFERENCE_FLAG);
 	if (!c)
 		return -1;
 	if (!channel)
@@ -5321,7 +5307,7 @@ static void t303_expiry(void *data)
 	} else if (c->t303_expirycnt < 2) {
 		c->cc.saved_ie_contents.length = 0;
 		c->cc.saved_ie_flags = 0;
-		if (ctrl->subchannel && !ctrl->bri)
+		if (ctrl->link.next && !ctrl->bri)
 			res = send_message(ctrl, c, Q931_SETUP, gr303_setup_ies);
 		else if (c->cis_call)
 			res = send_message(ctrl, c, Q931_SETUP, cis_setup_ies);
@@ -5366,7 +5352,7 @@ int q931_setup(struct pri *ctrl, q931_call *c, struct pri_sr *req)
 
 	c->ds1no = (req->channel & 0xff00) >> 8;
 	c->ds1explicit = (req->channel & 0x10000) >> 16;
-	if ((ctrl->localtype == PRI_CPE) && ctrl->subchannel && !ctrl->bri) {
+	if ((ctrl->localtype == PRI_CPE) && ctrl->link.next && !ctrl->bri) {
 		c->channelno = 0;
 		c->chanflags = 0;
 	} else {
@@ -5426,7 +5412,7 @@ int q931_setup(struct pri *ctrl, q931_call *c, struct pri_sr *req)
 	if (BRI_NT_PTMP(ctrl)) {
 		c->outboundbroadcast = 1;
 	}
-	if (ctrl->subchannel && !ctrl->bri)
+	if (ctrl->link.next && !ctrl->bri)
 		res = send_message(ctrl, c, Q931_SETUP, gr303_setup_ies);
 	else if (c->cis_call)
 		res = send_message(ctrl, c, Q931_SETUP, cis_setup_ies);
@@ -5554,7 +5540,7 @@ int q931_connect_acknowledge(struct pri *ctrl, q931_call *call, int channel)
 		winner->chanflags |= FLAG_EXCLUSIVE;
 	}
 	use_ies = NULL;
-	if (ctrl->subchannel && !ctrl->bri) {
+	if (ctrl->link.next && !ctrl->bri) {
 		if (ctrl->localtype == PRI_CPE) {
 			use_ies = gr303_connect_ack_ies;
 		}
@@ -6042,7 +6028,7 @@ static int __q931_hangup(struct pri *ctrl, q931_call *c, int cause)
 	case PRI_CAUSE_REQUESTED_CHAN_UNAVAIL:
 	case PRI_CAUSE_IDENTIFIED_CHANNEL_NOTEXIST:
 	case PRI_CAUSE_UNALLOCATED:
-		if (!PRI_MASTER(ctrl)->hangup_fix_enabled) {
+		if (!ctrl->hangup_fix_enabled) {
 			/* Legacy: We'll send RELEASE_COMPLETE with these causes */
 			disconnect = 0;
 			release_compl = 1;
@@ -6115,7 +6101,7 @@ static int __q931_hangup(struct pri *ctrl, q931_call *c, int cause)
 			if (ctrl->debug & PRI_DEBUG_Q931_STATE) {
 				pri_message(ctrl, "Faking clearing\n");
 			}
-			pri_create_fake_clearing(c, PRI_MASTER(ctrl));
+			pri_create_fake_clearing(c, ctrl);
 			/* This means that we never got a response from a TEI */
 			return 0;
 		}
@@ -6505,14 +6491,14 @@ static void q931_set_subcall_winner(struct q931_call *subcall)
 	}
 }
 
-static struct q931_call *q931_get_subcall(struct pri *link, struct q931_call *master_call)
+static struct q931_call *q931_get_subcall(struct q921_link *link, struct q931_call *master_call)
 {
 	int i;
 	struct q931_call *cur;
 	struct pri *ctrl;
 	int firstfree = -1;
 
-	ctrl = PRI_MASTER(link);
+	ctrl = link->ctrl;
 
 	/* First try to locate our subcall */
 	for (i = 0; i < ARRAY_LEN(master_call->subcalls); ++i) {
@@ -6564,7 +6550,7 @@ static struct q931_call *q931_get_subcall(struct pri *link, struct q931_call *ma
 	return cur;
 }
 
-int q931_receive(struct pri *link, q931_h *h, int len)
+int q931_receive(struct q921_link *link, q931_h *h, int len)
 {
 	q931_mh *mh;
 	struct q931_call *c;
@@ -6582,7 +6568,7 @@ int q931_receive(struct pri *link, q931_h *h, int len)
 	int allow_event;
 	int allow_posthandle;
 
-	ctrl = PRI_MASTER(link);
+	ctrl = link->ctrl;
 	memset(last_ie, 0, sizeof(last_ie));
 #ifdef LIBPRI_COUNTERS
 	ctrl->q931_rxcount++;
@@ -6622,7 +6608,7 @@ int q931_receive(struct pri *link, q931_h *h, int len)
 		pri_error(ctrl, "Unable to locate call %d\n", cref);
 		return -1;
 	}
-	if (c->master_call->outboundbroadcast && link != ctrl) {
+	if (c->master_call->outboundbroadcast && link != &ctrl->link) {
 		c = q931_get_subcall(link, c->master_call);
 		if (!c) {
 			pri_error(ctrl, "Unable to locate subcall for %d\n", cref);
@@ -7332,7 +7318,7 @@ int q931_cc_timeout(struct pri *ctrl, struct pri_cc_record *cc_record, enum CC_E
 	int fsm_complete;
 
 	q931_clr_subcommands(ctrl);
-	dummy = cc_record->master->dummy_call;
+	dummy = ctrl->link.dummy_call;
 	call = cc_record->signaling;
 	if (!call) {
 		/* Substitute the broadcast dummy call reference call. */
@@ -7361,7 +7347,7 @@ void q931_cc_indirect(struct pri *ctrl, struct pri_cc_record *cc_record, void (*
 	q931_call *dummy;
 
 	q931_clr_subcommands(ctrl);
-	dummy = cc_record->master->dummy_call;
+	dummy = ctrl->link.dummy_call;
 	call = cc_record->signaling;
 	if (!call) {
 		/* Substitute the broadcast dummy call reference call. */
@@ -7385,14 +7371,12 @@ void q931_cc_indirect(struct pri *ctrl, struct pri_cc_record *cc_record, void (*
  */
 struct q931_call *q931_find_link_id_call(struct pri *ctrl, int link_id)
 {
-	struct pri *master;
 	struct q931_call *cur;
 	struct q931_call *winner;
 	struct q931_call *match;
 
 	match = NULL;
-	master = PRI_MASTER(ctrl);
-	for (cur = *master->callpool; cur; cur = cur->next) {
+	for (cur = *ctrl->callpool; cur; cur = cur->next) {
 		if (cur->is_link_id_valid && cur->link_id == link_id) {
 			/* Found the link_id call. */
 			winner = q931_find_winning_call(cur);
@@ -7432,14 +7416,12 @@ struct q931_call *q931_find_link_id_call(struct pri *ctrl, int link_id)
  */
 struct q931_call *q931_find_held_active_call(struct pri *ctrl, struct q931_call *held_call)
 {
-	struct pri *master;
 	struct q931_call *cur;
 	struct q931_call *winner;
 	struct q931_call *match;
 
 	match = NULL;
-	master = PRI_MASTER(ctrl);
-	for (cur = *master->callpool; cur; cur = cur->next) {
+	for (cur = *ctrl->callpool; cur; cur = cur->next) {
 		if (cur->hold_state == Q931_HOLD_STATE_IDLE) {
 			/* Found an active call. */
 			winner = q931_find_winning_call(cur);
@@ -7486,14 +7468,12 @@ struct q931_call *q931_find_held_active_call(struct pri *ctrl, struct q931_call
  */
 static struct q931_call *q931_find_held_call(struct pri *ctrl, struct q931_call *active_call)
 {
-	struct pri *master;
 	struct q931_call *cur;
 	struct q931_call *winner;
 	struct q931_call *match;
 
 	match = NULL;
-	master = PRI_MASTER(ctrl);
-	for (cur = *master->callpool; cur; cur = cur->next) {
+	for (cur = *ctrl->callpool; cur; cur = cur->next) {
 		if (cur->hold_state == Q931_HOLD_STATE_CALL_HELD) {
 			/* Found a held call. */
 			winner = q931_find_winning_call(cur);
@@ -7702,7 +7682,7 @@ static int post_handle_q931_message(struct pri *ctrl, struct q931_mh *mh, struct
 		libpri_copy_string(ctrl->ev.answer.useruserinfo, c->useruserinfo, sizeof(ctrl->ev.answer.useruserinfo));
 		c->useruserinfo[0] = '\0';
 
-		if (!PRI_MASTER(ctrl)->manual_connect_ack) {
+		if (!ctrl->manual_connect_ack) {
 			q931_connect_acknowledge(ctrl, c, 0);
 		} else {
 			UPDATE_OURCALLSTATE(ctrl, c, Q931_CALL_STATE_CONNECT_REQUEST);
@@ -7804,7 +7784,7 @@ static int post_handle_q931_message(struct pri *ctrl, struct q931_mh *mh, struct
 		case Q931_CALL_STATE_ACTIVE:
 			UPDATE_OURCALLSTATE(ctrl, c, Q931_CALL_STATE_ACTIVE);
 			c->peercallstate = Q931_CALL_STATE_ACTIVE;
-			if (PRI_MASTER(ctrl)->manual_connect_ack) {
+			if (ctrl->manual_connect_ack) {
 				ctrl->ev.e = PRI_EVENT_CONNECT_ACK;
 				ctrl->ev.connect_ack.subcmds = &ctrl->subcmds;
 				ctrl->ev.connect_ack.channel = q931_encode_channel(c);
@@ -8185,7 +8165,7 @@ static int post_handle_q931_message(struct pri *ctrl, struct q931_mh *mh, struct
 		return res;
 	case Q931_HOLD:
 		res = 0;
-		if (!PRI_MASTER(ctrl)->hold_support) {
+		if (!ctrl->hold_support) {
 			/*
 			 * Blocking any calls from getting on HOLD effectively
 			 * disables HOLD/RETRIEVE.
@@ -8587,7 +8567,7 @@ static const char *q931_dl_event2str(enum Q931_DL_EVENT event)
  *
  * \return Nothing
  */
-void q931_dl_event(struct pri *link, enum Q931_DL_EVENT event)
+void q931_dl_event(struct q921_link *link, enum Q931_DL_EVENT event)
 {
 	struct q931_call *cur;
 	struct q931_call *call;
@@ -8598,8 +8578,7 @@ void q931_dl_event(struct pri *link, enum Q931_DL_EVENT event)
 		return;
 	}
 
-	/* Find the master - He has the call pool */
-	ctrl = PRI_MASTER(link);
+	ctrl = link->ctrl;
 
 	if (ctrl->debug & PRI_DEBUG_Q931_STATE) {
 		pri_message(ctrl, "TEI=%d DL event: %s(%d)\n", link->tei,