MNCC: split into generic mncc.c and mncc_builtin.c

The built-in code to handle call switching inside OpenBSC is
now in mncc_builtin.c, whereas some core/utility functions remain
in mncc.c
diff --git a/openbsc/src/mncc_builtin.c b/openbsc/src/mncc_builtin.c
new file mode 100644
index 0000000..87f724c
--- /dev/null
+++ b/openbsc/src/mncc_builtin.c
@@ -0,0 +1,400 @@
+/* mncc_builtin.c - default, minimal built-in MNCC Application for
+ *		    standalone bsc_hack (netowrk-in-the-box mode) */
+
+/* (C) 2008-2010 by Harald Welte <laforge@gnumonks.org>
+ * (C) 2009 by Andreas Eversberg <Andreas.Eversberg@versatel.de>
+ * All Rights Reserved
+ *
+ * This program is free software; you can redistribute it and/or modify
+ * it under the terms of the GNU General Public License as published by
+ * the Free Software Foundation; either version 2 of the License, or
+ * (at your option) any later version.
+ *
+ * This program is distributed in the hope that it will be useful,
+ * but WITHOUT ANY WARRANTY; without even the implied warranty of
+ * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+ * GNU General Public License for more details.
+ *
+ * You should have received a copy of the GNU General Public License along
+ * with this program; if not, write to the Free Software Foundation, Inc.,
+ * 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301 USA.
+ *
+ */
+
+
+#include <stdio.h>
+#include <stdlib.h>
+#include <string.h>
+#include <errno.h>
+#include <sys/types.h>
+
+#include <openbsc/gsm_04_08.h>
+#include <openbsc/debug.h>
+#include <openbsc/mncc.h>
+#include <osmocore/talloc.h>
+#include <openbsc/gsm_data.h>
+#include <openbsc/transaction.h>
+#include <openbsc/rtp_proxy.h>
+
+void *tall_call_ctx;
+
+static LLIST_HEAD(call_list);
+
+static u_int32_t new_callref = 0x00000001;
+
+static void free_call(struct gsm_call *call)
+{
+	llist_del(&call->entry);
+	DEBUGP(DMNCC, "(call %x) Call removed.\n", call->callref);
+	talloc_free(call);
+}
+
+
+static struct gsm_call *get_call_ref(u_int32_t callref)
+{
+	struct gsm_call *callt;
+
+	llist_for_each_entry(callt, &call_list, entry) {
+		if (callt->callref == callref)
+			return callt;
+	}
+	return NULL;
+}
+
+
+/* on incoming call, look up database and send setup to remote subscr. */
+static int mncc_setup_ind(struct gsm_call *call, int msg_type,
+			  struct gsm_mncc *setup)
+{
+	struct gsm_mncc mncc;
+	struct gsm_call *remote;
+
+	memset(&mncc, 0, sizeof(struct gsm_mncc));
+	mncc.callref = call->callref;
+
+	/* already have remote call */
+	if (call->remote_ref)
+		return 0;
+	
+	/* transfer mode 1 would be packet mode, which was never specified */
+	if (setup->bearer_cap.mode != 0) {
+		LOGP(DMNCC, LOGL_NOTICE, "(call %x) We don't support "
+			"packet mode\n", call->callref);
+		mncc_set_cause(&mncc, GSM48_CAUSE_LOC_PRN_S_LU,
+				GSM48_CC_CAUSE_BEARER_CA_UNAVAIL);
+		goto out_reject;
+	}
+
+	/* we currently only do speech */
+	if (setup->bearer_cap.transfer != GSM_MNCC_BCAP_SPEECH) {
+		LOGP(DMNCC, LOGL_NOTICE, "(call %x) We only support "
+			"voice calls\n", call->callref);
+		mncc_set_cause(&mncc, GSM48_CAUSE_LOC_PRN_S_LU,
+				GSM48_CC_CAUSE_BEARER_CA_UNAVAIL);
+		goto out_reject;
+	}
+
+	/* create remote call */
+	if (!(remote = talloc(tall_call_ctx, struct gsm_call))) {
+		mncc_set_cause(&mncc, GSM48_CAUSE_LOC_PRN_S_LU,
+				GSM48_CC_CAUSE_RESOURCE_UNAVAIL);
+		goto out_reject;
+	}
+	llist_add_tail(&remote->entry, &call_list);
+	remote->net = call->net;
+	remote->callref = new_callref++;
+	DEBUGP(DMNCC, "(call %x) Creating new remote instance %x.\n",
+		call->callref, remote->callref);
+
+	/* link remote call */
+	call->remote_ref = remote->callref;
+	remote->remote_ref = call->callref;
+
+	/* modify mode */
+	memset(&mncc, 0, sizeof(struct gsm_mncc));
+	mncc.callref = call->callref;
+	mncc.lchan_mode = GSM48_CMODE_SPEECH_EFR;
+	DEBUGP(DMNCC, "(call %x) Modify channel mode.\n", call->callref);
+	mncc_send(call->net, MNCC_LCHAN_MODIFY, &mncc);
+
+	/* send call proceeding */
+	memset(&mncc, 0, sizeof(struct gsm_mncc));
+	mncc.callref = call->callref;
+	DEBUGP(DMNCC, "(call %x) Accepting call.\n", call->callref);
+	mncc_send(call->net, MNCC_CALL_PROC_REQ, &mncc);
+
+	/* send setup to remote */
+//	setup->fields |= MNCC_F_SIGNAL;
+//	setup->signal = GSM48_SIGNAL_DIALTONE;
+	setup->callref = remote->callref;
+	DEBUGP(DMNCC, "(call %x) Forwarding SETUP to remote.\n", call->callref);
+	return mncc_send(remote->net, MNCC_SETUP_REQ, setup);
+
+out_reject:
+	mncc_send(call->net, MNCC_REJ_REQ, &mncc);
+	free_call(call);
+	return 0;
+}
+
+static int mncc_alert_ind(struct gsm_call *call, int msg_type,
+			  struct gsm_mncc *alert)
+{
+	struct gsm_call *remote;
+
+	/* send alerting to remote */
+	if (!(remote = get_call_ref(call->remote_ref)))
+		return 0;
+	alert->callref = remote->callref;
+	DEBUGP(DMNCC, "(call %x) Forwarding ALERT to remote.\n", call->callref);
+	return mncc_send(remote->net, MNCC_ALERT_REQ, alert);
+}
+
+static int mncc_notify_ind(struct gsm_call *call, int msg_type,
+			   struct gsm_mncc *notify)
+{
+	struct gsm_call *remote;
+
+	/* send notify to remote */
+	if (!(remote = get_call_ref(call->remote_ref)))
+		return 0;
+	notify->callref = remote->callref;
+	DEBUGP(DMNCC, "(call %x) Forwarding NOTIF to remote.\n", call->callref);
+	return mncc_send(remote->net, MNCC_NOTIFY_REQ, notify);
+}
+
+static int mncc_setup_cnf(struct gsm_call *call, int msg_type,
+			  struct gsm_mncc *connect)
+{
+	struct gsm_mncc connect_ack, frame_recv;
+	struct gsm_network *net = call->net;
+	struct gsm_call *remote;
+	u_int32_t refs[2];
+
+	/* acknowledge connect */
+	memset(&connect_ack, 0, sizeof(struct gsm_mncc));
+	connect_ack.callref = call->callref;
+	DEBUGP(DMNCC, "(call %x) Acknowledge SETUP.\n", call->callref);
+	mncc_send(call->net, MNCC_SETUP_COMPL_REQ, &connect_ack);
+
+	/* send connect message to remote */
+	if (!(remote = get_call_ref(call->remote_ref)))
+		return 0;
+	connect->callref = remote->callref;
+	DEBUGP(DMNCC, "(call %x) Sending CONNECT to remote.\n", call->callref);
+	mncc_send(remote->net, MNCC_SETUP_RSP, connect);
+
+	/* bridge tch */
+	refs[0] = call->callref;
+	refs[1] = call->remote_ref;
+	DEBUGP(DMNCC, "(call %x) Bridging with remote.\n", call->callref);
+
+	/* in direct mode, we always have to bridge the channels */
+	if (ipacc_rtp_direct)
+		return mncc_send(call->net, MNCC_BRIDGE, refs);
+
+	/* proxy mode */
+	if (!net->handover.active) {
+		/* in the no-handover case, we can bridge, i.e. use
+		 * the old RTP proxy code */
+		return mncc_send(call->net, MNCC_BRIDGE, refs);
+	} else {
+		/* in case of handover, we need to re-write the RTP
+		 * SSRC, sequence and timestamp values and thus
+		 * need to enable RTP receive for both directions */
+		memset(&frame_recv, 0, sizeof(struct gsm_mncc));
+		frame_recv.callref = call->callref;
+		mncc_send(call->net, MNCC_FRAME_RECV, &frame_recv);
+		frame_recv.callref = call->remote_ref;
+		return mncc_send(call->net, MNCC_FRAME_RECV, &frame_recv);
+	}
+}
+
+static int mncc_disc_ind(struct gsm_call *call, int msg_type,
+			 struct gsm_mncc *disc)
+{
+	struct gsm_call *remote;
+
+	/* send release */
+	DEBUGP(DMNCC, "(call %x) Releasing call with cause %d\n",
+		call->callref, disc->cause.value);
+	mncc_send(call->net, MNCC_REL_REQ, disc);
+
+	/* send disc to remote */
+	if (!(remote = get_call_ref(call->remote_ref))) {
+		return 0;
+	}
+	disc->callref = remote->callref;
+	DEBUGP(DMNCC, "(call %x) Disconnecting remote with cause %d\n",
+		remote->callref, disc->cause.value);
+	return mncc_send(remote->net, MNCC_DISC_REQ, disc);
+}
+
+static int mncc_rel_ind(struct gsm_call *call, int msg_type, struct gsm_mncc *rel)
+{
+	struct gsm_call *remote;
+
+	/* send release to remote */
+	if (!(remote = get_call_ref(call->remote_ref))) {
+		free_call(call);
+		return 0;
+	}
+	rel->callref = remote->callref;
+	DEBUGP(DMNCC, "(call %x) Releasing remote with cause %d\n",
+		call->callref, rel->cause.value);
+	mncc_send(remote->net, MNCC_REL_REQ, rel);
+
+	free_call(call);
+
+	return 0;
+}
+
+static int mncc_rel_cnf(struct gsm_call *call, int msg_type, struct gsm_mncc *rel)
+{
+	free_call(call);
+	return 0;
+}
+
+/* receiving a TCH/F frame from the BSC code */
+static int mncc_rcv_tchf(struct gsm_call *call, int msg_type,
+			 struct gsm_data_frame *dfr)
+{
+	struct gsm_trans *remote_trans;
+
+	remote_trans = trans_find_by_callref(call->net, call->remote_ref);
+
+	/* this shouldn't really happen */
+	if (!remote_trans || !remote_trans->conn) {
+		LOGP(DMNCC, LOGL_ERROR, "No transaction or transaction without lchan?!?\n");
+		return -EIO;
+	}
+
+	/* RTP socket of remote end has meanwhile died */
+	if (!remote_trans->conn->lchan->abis_ip.rtp_socket)
+		return -EIO;
+
+	return rtp_send_frame(remote_trans->conn->lchan->abis_ip.rtp_socket, dfr);
+}
+
+
+/* Internal MNCC handler input function (from CC -> MNCC -> here) */
+int int_mncc_recv(struct gsm_network *net, int msg_type, void *arg)
+{
+	struct gsm_mncc *data = arg;
+	int callref;
+	struct gsm_call *call = NULL, *callt;
+	int rc = 0;
+
+	/* Special messages */
+	switch(msg_type) {
+	}
+	
+	/* find callref */
+	callref = data->callref;
+	llist_for_each_entry(callt, &call_list, entry) {
+		if (callt->callref == callref) {
+			call = callt;
+			break;
+		}
+	}
+
+	/* create callref, if setup is received */
+	if (!call) {
+		if (msg_type != MNCC_SETUP_IND)
+			return 0; /* drop */
+		/* create call */
+		if (!(call = talloc_zero(tall_call_ctx, struct gsm_call))) {
+			struct gsm_mncc rel;
+			
+			memset(&rel, 0, sizeof(struct gsm_mncc));
+			rel.callref = callref;
+			mncc_set_cause(&rel, GSM48_CAUSE_LOC_PRN_S_LU,
+				       GSM48_CC_CAUSE_RESOURCE_UNAVAIL);
+			mncc_send(net, MNCC_REL_REQ, &rel);
+			return 0;
+		}
+		llist_add_tail(&call->entry, &call_list);
+		call->net = net;
+		call->callref = callref;
+		DEBUGP(DMNCC, "(call %x) Call created.\n", call->callref);
+	}
+
+	switch (msg_type) {
+	case GSM_TCHF_FRAME:
+	case GSM_TCHF_FRAME_EFR:
+		break;
+	default:
+		DEBUGP(DMNCC, "(call %x) Received message %s\n", call->callref,
+			get_mncc_name(msg_type));
+		break;
+	}
+
+	switch(msg_type) {
+	case MNCC_SETUP_IND:
+		rc = mncc_setup_ind(call, msg_type, arg);
+		break;
+	case MNCC_SETUP_CNF:
+		rc = mncc_setup_cnf(call, msg_type, arg);
+		break;
+	case MNCC_SETUP_COMPL_IND:
+		break;
+	case MNCC_CALL_CONF_IND:
+		/* we now need to MODIFY the channel */
+		data->lchan_mode = GSM48_CMODE_SPEECH_EFR;
+		mncc_send(call->net, MNCC_LCHAN_MODIFY, data);
+		break;
+	case MNCC_ALERT_IND:
+		rc = mncc_alert_ind(call, msg_type, arg);
+		break;
+	case MNCC_NOTIFY_IND:
+		rc = mncc_notify_ind(call, msg_type, arg);
+		break;
+	case MNCC_DISC_IND:
+		rc = mncc_disc_ind(call, msg_type, arg);
+		break;
+	case MNCC_REL_IND:
+	case MNCC_REJ_IND:
+		rc = mncc_rel_ind(call, msg_type, arg);
+		break;
+	case MNCC_REL_CNF:
+		rc = mncc_rel_cnf(call, msg_type, arg);
+		break;
+	case MNCC_FACILITY_IND:
+		break;
+	case MNCC_START_DTMF_IND:
+		break;
+	case MNCC_STOP_DTMF_IND:
+		break;
+	case MNCC_MODIFY_IND:
+		mncc_set_cause(data, GSM48_CAUSE_LOC_PRN_S_LU,
+				GSM48_CC_CAUSE_SERV_OPT_UNIMPL);
+		DEBUGP(DMNCC, "(call %x) Rejecting MODIFY with cause %d\n",
+			call->callref, data->cause.value);
+		rc = mncc_send(net, MNCC_MODIFY_REJ, data);
+		break;
+	case MNCC_MODIFY_CNF:
+		break;
+	case MNCC_HOLD_IND:
+		mncc_set_cause(data, GSM48_CAUSE_LOC_PRN_S_LU,
+				GSM48_CC_CAUSE_SERV_OPT_UNIMPL);
+		DEBUGP(DMNCC, "(call %x) Rejecting HOLD with cause %d\n",
+			call->callref, data->cause.value);
+		rc = mncc_send(net, MNCC_HOLD_REJ, data);
+		break;
+	case MNCC_RETRIEVE_IND:
+		mncc_set_cause(data, GSM48_CAUSE_LOC_PRN_S_LU,
+				GSM48_CC_CAUSE_SERV_OPT_UNIMPL);
+		DEBUGP(DMNCC, "(call %x) Rejecting RETRIEVE with cause %d\n",
+			call->callref, data->cause.value);
+		rc = mncc_send(net, MNCC_RETRIEVE_REJ, data);
+		break;
+	case GSM_TCHF_FRAME:
+	case GSM_TCHF_FRAME_EFR:
+		rc = mncc_rcv_tchf(call, msg_type, arg);
+		break;
+	default:
+		LOGP(DMNCC, LOGL_NOTICE, "(call %x) Message unhandled\n", callref);
+		break;
+	}
+
+	return rc;
+}