nitb: Add a mode to not use TMSI for normal operation

In case foreign simcards are used we can not do authentication
and ciphering. In case a TMSI is re-used too early and we do
page using TMSI we can't know which of the two MS is responding
to us. We could change the "secure channel" routine to ask for
the IMSI and only then stop the paging.

As we don't have ciphering there is not much use in using the
TMSI. Add a mode "no assign-tmsi" that will not assign the TMSI
during LU. Now CM Service Request and Paging Response  will
work using the IMSI. There can't be a clash with that.

[ciaby fixed the vty write to use the right name]

1 files changed, 22 insertions, 0 deletions

diff --git a/openbsc/src/libmsc/vty_interface_layer3.c b/openbsc/src/libmsc/vty_interface_layer3.c
index 6cf51a33f..1515aea0a 100644
--- a/openbsc/src/libmsc/vty_interface_layer3.c
+++ b/openbsc/src/libmsc/vty_interface_layer3.c
@@ -1037,12 +1037,32 @@ DEFUN(cfg_nitb_no_subscr_create, cfg_nitb_no_subscr_create_cmd,
 	return CMD_SUCCESS;
 }
 
+DEFUN(cfg_nitb_assign_tmsi, cfg_nitb_assign_tmsi_cmd,
+      "assign-tmsi",
+      "Assign TMSI during Location Updating.\n")
+{
+	struct gsm_network *gsmnet = gsmnet_from_vty(vty);
+	gsmnet->avoid_tmsi = 0;
+	return CMD_SUCCESS;
+}
+
+DEFUN(cfg_nitb_no_assign_tmsi, cfg_nitb_no_assign_tmsi_cmd,
+      "no assign-tmsi",
+      NO_STR "Assign TMSI during Location Updating.\n")
+{
+	struct gsm_network *gsmnet = gsmnet_from_vty(vty);
+	gsmnet->avoid_tmsi = 1;
+	return CMD_SUCCESS;
+}
+
 static int config_write_nitb(struct vty *vty)
 {
 	struct gsm_network *gsmnet = gsmnet_from_vty(vty);
 	vty_out(vty, "nitb%s", VTY_NEWLINE);
 	vty_out(vty, " %ssubscriber-create-on-demand%s",
 		gsmnet->create_subscriber ? "" : "no ", VTY_NEWLINE);
+	vty_out(vty, " %sassign-tmsi%s",
+		gsmnet->avoid_tmsi ? "no " : "", VTY_NEWLINE);
 	return CMD_SUCCESS;
 }
 
@@ -1096,6 +1116,8 @@ int bsc_vty_init_extra(void)
 	install_node(&nitb_node, config_write_nitb);
 	install_element(NITB_NODE, &cfg_nitb_subscr_create_cmd);
 	install_element(NITB_NODE, &cfg_nitb_no_subscr_create_cmd);
+	install_element(NITB_NODE, &cfg_nitb_assign_tmsi_cmd);
+	install_element(NITB_NODE, &cfg_nitb_no_assign_tmsi_cmd);
 
 	return 0;
 }