[PATCH 2/2] gprs: Ignore NS RESET_ACK and ALIVE_ACK without RESET

[Jacob Erlbeck]

Currently those messages are answered by a NS_STATUS message when
received on an uninitialised (no NS_RESET hat been seen yet) NS_VC
which violates GPP TS 08.16 7.3.1 and 7.4.1.

This patch adds checks to gprs_ns_vc_create() and eventually returns
before the error NS_STATUS message is generated.

Sponsored-by: On-Waves ehf
---
 src/gb/gprs_ns.c         |   17 +++++++++++++++++
 tests/gb/gprs_ns_test.ok |    6 ------
 2 files changed, 17 insertions(+), 6 deletions(-)

diff --git a/src/gb/gprs_ns.c b/src/gb/gprs_ns.c
index 0e9156a..55535ad 100644
--- a/src/gb/gprs_ns.c
+++ b/src/gb/gprs_ns.c
@@ -1127,12 +1127,29 @@ int gprs_ns_vc_create(struct gprs_ns_inst *nsi, struct msgb *msg,
 	int rc;
 
 	if (nsh->pdu_type == NS_PDUT_STATUS) {
+		/* Do not respond, see 3GPP TS 08.16, 7.5.1 */
 		LOGP(DNS, LOGL_INFO, "Ignoring NS STATUS from %s "
 		     "for non-existing NS-VC\n",
 		     gprs_ns_ll_str(fallback_nsvc));
 		return GPRS_NS_CS_SKIPPED;
 	}
 
+	if (nsh->pdu_type == NS_PDUT_ALIVE_ACK) {
+		/* Ignore this, see 3GPP TS 08.16, 7.4.1 */
+		LOGP(DNS, LOGL_INFO, "Ignoring NS ALIVE ACK from %s "
+		     "for non-existing NS-VC\n",
+		     gprs_ns_ll_str(fallback_nsvc));
+		return GPRS_NS_CS_SKIPPED;
+	}
+
+	if (nsh->pdu_type == NS_PDUT_RESET_ACK) {
+		/* Ignore this, see 3GPP TS 08.16, 7.3.1 */
+		LOGP(DNS, LOGL_INFO, "Ignoring NS RESET ACK from %s "
+		     "for non-existing NS-VC\n",
+		     gprs_ns_ll_str(fallback_nsvc));
+		return GPRS_NS_CS_SKIPPED;
+	}
+
 	/* Only the RESET procedure creates a new NSVC */
 	if (nsh->pdu_type != NS_PDUT_RESET) {
 		/* Since we have no NSVC, we have to use a fake */
diff --git a/tests/gb/gprs_ns_test.ok b/tests/gb/gprs_ns_test.ok
index 23c9e5f..13d5f36 100644
--- a/tests/gb/gprs_ns_test.ok
+++ b/tests/gb/gprs_ns_test.ok
@@ -97,9 +97,6 @@ result (STATUS) = 0
 PROCESSING ALIVE_ACK from 0x01020304:1111
 0b 
 
-MESSAGE to BSS, msg length 7
-08 00 81 0a 02 81 0b 
-
 result (ALIVE_ACK) = 0
 
 --- Send unexpected NS RESET ACK (should not be answered)---
@@ -107,9 +104,6 @@ result (ALIVE_ACK) = 0
 PROCESSING RESET_ACK from 0x01020304:1111
 03 01 82 e0 01 04 82 e0 00 
 
-MESSAGE to BSS, msg length 15
-08 00 81 0a 02 89 03 01 82 e0 01 04 82 e0 00 
-
 result (RESET_ACK) = 0
 
 --- Setup, send BSSGP RESET ---
-- 
1.7.9.5