allow CM Service Request on already open connection

Change-Id: I3c4687aafe495e60b1568e6505dbf847adab37f1

2 files changed, 78 insertions, 13 deletions

diff --git a/openbsc/src/libmsc/gsm_04_08.c b/openbsc/src/libmsc/gsm_04_08.c
index 68ac3cf86..8b7d3bdd1 100644
--- a/openbsc/src/libmsc/gsm_04_08.c
+++ b/openbsc/src/libmsc/gsm_04_08.c
@@ -598,6 +598,49 @@ int gsm48_tx_mm_auth_rej(struct gsm_subscriber_connection *conn)
 	return gsm48_tx_simple(conn, GSM48_PDISC_MM, GSM48_MT_MM_AUTH_REJ);
 }
 
+#define CONN_REUSE 1
+#if CONN_REUSE
+static int msc_vlr_tx_cm_serv_acc(void *msc_conn_ref);
+static int msc_vlr_tx_cm_serv_rej(void *msc_conn_ref, enum vlr_proc_arq_result result);
+
+int cm_serv_conn_reuse(struct gsm_subscriber_connection *conn,
+		       const uint8_t *mi_lv)
+{
+	struct vlr_subscr *vsub;
+	uint8_t mi_type;
+	char mi_string[GSM48_MI_SIZE];
+	uint32_t tmsi;
+
+	gsm48_mi_to_string(mi_string, sizeof(mi_string), mi_lv+1, mi_lv[0]);
+	mi_type = mi_lv[1] & GSM_MI_TYPE_MASK;
+
+	switch (mi_type) {
+	case GSM_MI_TYPE_IMSI:
+		vsub = vlr_subscr_find_by_imsi(conn->network->vlr, mi_string);
+		break;
+	case GSM_MI_TYPE_TMSI:
+		tmsi = osmo_load32be(mi_lv+2);
+		vsub = vlr_subscr_find_by_tmsi(conn->network->vlr, tmsi);
+		break;
+	case GSM_MI_TYPE_IMEI:
+		/* TODO: IMEI (emergency call) */
+	default:
+		vsub = NULL;
+		break;
+	}
+
+	if (!vsub) {
+		msc_vlr_tx_cm_serv_rej(conn, VLR_PR_ARQ_RES_ILLEGAL_SUBSCR);
+		return -EINVAL;
+	}
+
+	DEBUGP(DMM, "%s: re-using already accepted connection\n",
+	       vlr_subscr_name(vsub));
+	conn->received_cm_service_request = true;
+	return conn->network->vlr->ops.tx_cm_serv_acc(conn);
+}
+#endif
+
 /*
  * Handle CM Service Requests
  * a) Verify that the packet is long enough to contain the information
@@ -664,14 +707,26 @@ int gsm48_rx_mm_serv_req(struct gsm_subscriber_connection *conn, struct msgb *ms
 	}
 
 	osmo_signal_dispatch(SS_SUBSCR, S_SUBSCR_IDENTITY, (classmark2 + classmark2_len));
+	memcpy(conn->classmark.classmark2, classmark2, classmark2_len);
+	conn->classmark.classmark2_len = classmark2_len;
+
+#if CONN_REUSE
+	if (conn->conn_fsm) {
+		if (msc_subscr_conn_is_accepted(conn))
+			return cm_serv_conn_reuse(conn, mi-1);
+		LOGP(DMM, LOGL_ERROR, "%s: connection already in use\n",
+		     vlr_subscr_name(conn->vsub));
+		msc_vlr_tx_cm_serv_rej(conn, VLR_PR_ARQ_RES_UNKNOWN_ERROR);
+		return -EINVAL;
+	}
+#endif
 
 	rc = msc_create_conn_fsm(conn, mi_string);
-	if (rc)
+	if (rc) {
+		msc_vlr_tx_cm_serv_rej(conn, VLR_PR_ARQ_RES_UNKNOWN_ERROR);
 		/* logging already happened in msc_create_conn_fsm() */
 		return rc;
-
-	memcpy(conn->classmark.classmark2, classmark2, classmark2_len);
-	conn->classmark.classmark2_len = classmark2_len;
+	}
 
 #if BEFORE_MSCSPLIT
 	/* see mail on openbsc@ 9 Feb 2016 22:30:15 +0100
diff --git a/openbsc/tests/msc_vlr/msc_vlr_test_reject_concurrency.c b/openbsc/tests/msc_vlr/msc_vlr_test_reject_concurrency.c
index 52757fea4..bace73ba3 100644
--- a/openbsc/tests/msc_vlr/msc_vlr_test_reject_concurrency.c
+++ b/openbsc/tests/msc_vlr/msc_vlr_test_reject_concurrency.c
@@ -164,7 +164,7 @@ void _paging_resp_part1()
 	EXPECT_CONN_COUNT(1);
 }
 
-void _paging_resp_part2()
+void _paging_resp_part2(int expect_conn_count)
 {
 	btw("MS replies with CP-ACK for received SMS");
 	ms_sends_msg("8904");
@@ -175,8 +175,8 @@ void _paging_resp_part2()
 	ms_sends_msg("890106020041020000");
 	VERBOSE_ASSERT(dtap_tx_confirmed, == true, "%d");
 
-	btw("SMS is done, conn is gone");
-	EXPECT_CONN_COUNT(0);
+	btw("SMS is done");
+	EXPECT_CONN_COUNT(expect_conn_count);
 }
 
 void test_reject_lu_during_lu()
@@ -242,10 +242,15 @@ void test_reject_lu_during_cm()
 	_normal_lu();
 	_normal_cm_service_req();
 
-	btw("An erratic LU request on the same conn results in conn termination");
+	btw("A LU request on an open conn is dropped silently");
+	/* TODO: accept periodic LU on an already open conn? */
 	lu_result_sent = RES_NONE;
 	ms_sends_msg("050802008168000130089910070000006402");
 	VERBOSE_ASSERT(lu_result_sent, == RES_NONE, "%d");
+	EXPECT_CONN_COUNT(1);
+
+	BTW("subscriber detaches");
+	ms_sends_msg("050130089910070000006402");
 	EXPECT_CONN_COUNT(0);
 
 	clear_vlr();
@@ -303,7 +308,7 @@ void test_reject_paging_resp_during_paging_resp()
 	BTW("MS sends another erratic Paging Response which is dropped silently");
 	ms_sends_msg("06270703305882089910070000006402");
 
-	_paging_resp_part2();
+	_paging_resp_part2(0);
 
 	clear_vlr();
 	comment_end();
@@ -323,7 +328,7 @@ void test_reject_lu_during_paging_resp()
 	VERBOSE_ASSERT(lu_result_sent, == RES_NONE, "%d");
 	EXPECT_CONN_COUNT(1);
 
-	_paging_resp_part2();
+	_paging_resp_part2(0);
 
 	clear_vlr();
 	comment_end();
@@ -337,13 +342,18 @@ void test_reject_cm_during_paging_resp()
 	_page();
 	_paging_resp_part1();
 
-	BTW("MS sends erratic CM Service Request, which is dropped silently");
+	BTW("CM Service Request during open connection is accepted");
 	cm_service_result_sent = RES_NONE;
 	ms_sends_msg("05247803305886089910070000006402");
-	VERBOSE_ASSERT(cm_service_result_sent, == RES_NONE, "%d");
+	VERBOSE_ASSERT(cm_service_result_sent, == RES_ACCEPT, "%d");
 	EXPECT_CONN_COUNT(1);
+	VERBOSE_ASSERT(g_conn->received_cm_service_request, == true, "%d");
+
+	_paging_resp_part2(1);
 
-	_paging_resp_part2();
+	BTW("subscriber detaches");
+	ms_sends_msg("050130089910070000006402");
+	EXPECT_CONN_COUNT(0);
 
 	clear_vlr();
 	comment_end();