Add "silent call" feature to OpenBSC

This allows the administrator to use the vty interface to issue a silent
call to a given subscriber by using
	"subscriber extension XXXX silent call start"
and stopping that silent call with
	"subscriber extension XXXX silent call stop"

openbsc/include/openbsc/signal.h

@@ -39,6 +39,7 @@ enum signal_subsystems {
 	SS_NM,
 	SS_LCHAN,
 	SS_SUBSCR,
+	SS_SCALL,
 };
 
 /* SS_PAGING signals */
@@ -85,6 +86,13 @@ enum signal_subscr {
 	S_SUBSCR_DETACHED,
 };
 
+/* SS_SCALL signals */
+enum signal_scall {
+	S_SCALL_SUCCESS,
+	S_SCALL_EXPIRED,
+	S_SCALL_DETACHED,
+};
+
 typedef int signal_cbfn(unsigned int subsys, unsigned int signal,
 			void *handler_data, void *signal_data);
 
@@ -96,6 +104,12 @@ struct paging_signal_data {
 	struct gsm_lchan *lchan;
 };
 
+struct scall_signal_data {
+	struct gsm_subscriber *subscr;
+	struct gsm_lchan *lchan;
+	void *data;
+};
+
 /* Management */
 int register_signal_handler(unsigned int subsys, signal_cbfn *cbfn, void *data);
 void unregister_signal_handler(unsigned int subsys, signal_cbfn *cbfn, void *data);

openbsc/src/Makefile.am

@@ -14,7 +14,7 @@ libbsc_a_SOURCES = abis_rsl.c abis_nm.c gsm_data.c gsm_04_08_utils.c \
 
 libmsc_a_SOURCES = gsm_subscriber.c db.c telnet_interface.c \
 		mncc.c rtp_proxy.c gsm_04_08.c gsm_04_11.c transaction.c \
-		token_auth.c rrlp.c gsm_04_80.c ussd.c
+		token_auth.c rrlp.c gsm_04_80.c ussd.c silent_call.c
 
 libvty_a_SOURCES = vty/buffer.c vty/command.c vty/vector.c vty/vty.c
 

openbsc/src/silent_call.c

@@ -0,0 +1,92 @@
+/* GSM silent call feature */
+
+/*
+ * (C) 2009 by Harald Welte <laforge@gnumonks.org>
+ *
+ * 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 <stdlib.h>
+#include <unistd.h>
+#include <errno.h>
+
+#include <openbsc/msgb.h>
+#include <openbsc/signal.h>
+#include <openbsc/debug.h>
+#include <openbsc/paging.h>
+#include <openbsc/gsm_data.h>
+#include <openbsc/gsm_subscriber.h>
+#include <openbsc/abis_rsl.h>
+
+static int paging_cb_silent(unsigned int hooknum, unsigned int event,
+			    struct msgb *msg, void *_lchan, void *_data)
+{
+	struct gsm_lchan *lchan = _lchan;
+	struct scall_signal_data sigdata;
+	int rc;
+
+	if (hooknum != GSM_HOOK_RR_PAGING)
+		return -EINVAL;
+
+	DEBUGP(DSMS, "paging_cb_silent: ");
+
+	sigdata.lchan = lchan;
+	sigdata.data = _data;
+
+	switch (event) {
+	case GSM_PAGING_SUCCEEDED:
+		DEBUGPC(DSMS, "success, using Timeslot %u on ARFCN %u\n",
+			lchan->ts->nr, lchan->ts->trx->arfcn);
+		/* increment lchan reference count */
+		dispatch_signal(SS_SCALL, S_SCALL_SUCCESS, &sigdata);
+		use_lchan(lchan);
+		break;
+	case GSM_PAGING_EXPIRED:
+		DEBUGP(DSMS, "expired\n");
+		dispatch_signal(SS_SCALL, S_SCALL_EXPIRED, &sigdata);
+		break;
+	default:
+		rc = -EINVAL;
+		break;
+	}
+
+	return rc;
+}
+
+int gsm_silent_call_start(struct gsm_subscriber *subscr, void *data)
+{
+	int rc;
+
+	rc = paging_request(subscr->net, subscr, RSL_CHANNEED_TCH_F,
+			    paging_cb_silent, data);
+	return rc;
+}
+
+int gsm_silent_call_stop(struct gsm_subscriber *subscr)
+{
+	struct gsm_lchan *lchan;
+
+	lchan = lchan_for_subscr(subscr);
+	if (!lchan)
+		return -EINVAL;
+
+	/* FIXME: did we actually establish a silent call for this guy? */
+	put_lchan(lchan);
+
+	return 0;
+}

openbsc/src/vty_interface_layer3.c

@@ -38,6 +38,7 @@
 #include <openbsc/gsm_utils.h>
 #include <openbsc/db.h>
 #include <openbsc/talloc.h>
+#include <openbsc/signal.h>
 
 /* forward declarations */
 void subscr_dump_vty(struct vty *vty, struct gsm_subscriber *subscr);
@@ -55,7 +56,6 @@ static int dummy_config_write(struct vty *v)
 	return CMD_SUCCESS;
 }
 
-
 static struct buffer *argv_to_buffer(int argc, const char *argv[], int base)
 {
 	struct buffer *b = buffer_new(1024);
@@ -259,6 +259,38 @@ DEFUN(subscriber_silent_sms,
 	return rc;
 }
 
+DEFUN(subscriber_silent_call,
+      subscriber_silent_call_cmd,
+      "subscriber " SUBSCR_TYPES " EXTEN silent call (start|stop)",
+      "Send a silent call to a subscriber")
+{
+	struct gsm_subscriber *subscr = get_subscr_by_argv(argv[0], argv[1]);
+	int rc;
+
+	if (!subscr) {
+		vty_out(vty, "%% No subscriber found for %s %s%s",
+			argv[0], argv[1]);
+		return CMD_WARNING;
+	}
+
+	if (!strcmp(argv[2], "start")) {
+		rc = gsm_silent_call_start(subscr, vty);
+		if (rc <= 0) {
+			vty_out(vty, "%% Subscriber not attached%s",
+				VTY_NEWLINE);
+			return CMD_WARNING;
+		}
+	} else {
+		rc = gsm_silent_call_stop(subscr);
+		if (rc < 0)
+			return CMD_WARNING;
+	}
+
+	subscr_put(subscr);
+
+	return CMD_SUCCESS;
+}
+
 DEFUN(cfg_subscr_name,
       cfg_subscr_name_cmd,
       "name NAME",
@@ -307,10 +339,31 @@ DEFUN(cfg_subscr_authorized,
 	return CMD_SUCCESS;
 }
 
+static int scall_cbfn(unsigned int subsys, unsigned int signal,
+			void *handler_data, void *signal_data)
+{
+	struct scall_signal_data *sigdata = signal_data;
+	struct vty *vty = sigdata->data;
+
+	switch (signal) {
+	case S_SCALL_SUCCESS:
+		vty_out(vty, "%% silent call on ARFCN %u timeslot %u%s",
+			sigdata->lchan->ts->trx->arfcn, sigdata->lchan->ts->nr,
+			VTY_NEWLINE);
+		break;
+	case S_SCALL_EXPIRED:
+		vty_out(vty, "%% silent call expired paging%s", VTY_NEWLINE);
+		break;
+	}
+	return 0;
+}
+
 int bsc_vty_init_extra(struct gsm_network *net)
 {
 	gsmnet = net;
 
+	register_signal_handler(SS_SCALL, scall_cbfn, NULL);
+
 	install_element(VIEW_NODE, &show_subscr_cmd);
 	install_element(VIEW_NODE, &show_subscr_cache_cmd);
 
@@ -318,6 +371,7 @@ int bsc_vty_init_extra(struct gsm_network *net)
 
 	install_element(VIEW_NODE, &subscriber_send_sms_cmd);
 	install_element(VIEW_NODE, &subscriber_silent_sms_cmd);
+	install_element(VIEW_NODE, &subscriber_silent_call_cmd);
 
 	install_element(CONFIG_NODE, &cfg_subscr_cmd);
 	install_node(&subscr_node, dummy_config_write);