patch: callref bugfix

[Andreas.Eversberg]

this patch will correct some callref behavior.

if a message with an unknown callref is received, a release is sent to
the other layer.
if a release with an unknown callref is received, it is ignored.
no message is sent, if the callref is already gone.


diff --git a/openbsc/src/gsm_04_08.c b/openbsc/src/gsm_04_08.c
index d6e161a..3f12546 100644
--- a/openbsc/src/gsm_04_08.c
+++ b/openbsc/src/gsm_04_08.c
@@ -1705,6 +1705,10 @@ static int mncc_recvmsg(struct gsm_network *net,
struct gsm_trans *trans,
 {
 	struct msgb *msg;
 
+	/* don't send message, if call is not associated anymore */
+	if (!mncc->callref)
+		return 0;
+
 	if (trans)
 		if (trans->lchan)
 			DEBUGP(DCC, "(bts %d trx %d ts %d ti %x sub %s)
"
@@ -3242,10 +3246,12 @@ int mncc_send(struct gsm_network *net, int
msg_type, void *arg)
 	if (!trans) {
 		struct gsm_subscriber *subscr;
 
+		if (msg_type == MNCC_REL_REQ)
+			return 0; /* drop */
 		if (msg_type != MNCC_SETUP_REQ) {
 			DEBUGP(DCC, "(bts - trx - ts - ti -- sub %s) "
 				"Received '%s' from MNCC with "
-				"unknown callref %d\n",
data->called.number,
+				"unknown callref %x\n",
data->called.number,
 				get_mncc_name(msg_type), data->callref);
 			/* Invalid call reference */
 			return mncc_release_ind(net, NULL,
data->callref,
diff --git a/openbsc/src/mncc.c b/openbsc/src/mncc.c
index f62541c..1874750 100644
--- a/openbsc/src/mncc.c
+++ b/openbsc/src/mncc.c
@@ -301,8 +301,20 @@ int mncc_recv(struct gsm_network *net, int
msg_type, void *arg)
 
 	/* create callref, if setup is received */
 	if (!call) {
-		if (msg_type != MNCC_SETUP_IND)
+		if (msg_type == MNCC_REL_IND)
 			return 0; /* drop */
+		if (msg_type != MNCC_SETUP_IND) {
+			struct gsm_mncc rel;
+			
+			DEBUGP(DMNCC, "(call %x) Rejecting message %s
with unknown ref.\n",
+				callref, get_mncc_name(msg_type));
+			memset(&rel, 0, sizeof(struct gsm_mncc));
+			rel.callref = callref;
+			mncc_set_cause(&rel, GSM48_CAUSE_LOC_PRN_S_LU,
+				       GSM48_CC_CAUSE_INVAL_TRANS_ID);
+			mncc_send(net, MNCC_REL_REQ, &rel);
+			return 0;
+		}
 		/* create call */
 		if (!(call = talloc_zero(tall_call_ctx, struct
gsm_call))) {
 			struct gsm_mncc rel;