Change in osmo-sgsn[master]: gprs_gmm: send Service Reject when no PDP ctxs are available.

[Mykola Shchetinin]

Mykola Shchetinin has submitted this change and it was merged. ( https://gerrit.osmocom.org/13744 )

Change subject: gprs_gmm: send Service Reject when no PDP ctxs are available.
......................................................................

gprs_gmm: send Service Reject when no PDP ctxs are available.

Look at PDP Context Status IE: if there are any PDP contexts which are
ACTIVE on MS side and there are no PDP contexts which are ACTIVE on the
network side, then send Service Reject with the cause "NO PDP
ACTIVATED". This forces MS to reactivate the PDP contexts.

3GPP TS 24.008 Section 4.7.13.4 Service request procedure not accepted
by the network. Cause # 40.

Fixes: OS#3937
Change-Id: If610cbef17c25ec44e65d4f1b2340d102c560437
---
M src/gprs/gprs_gmm.c
M tests/sgsn/sgsn_test.c
M tests/sgsn/sgsn_test.ok
3 files changed, 43 insertions(+), 1 deletion(-)

Approvals:
  lynxis lazus: Looks good to me, approved
  Mykola Shchetinin: Looks good to me, but someone else must approve
  Jenkins Builder: Verified



diff --git a/src/gprs/gprs_gmm.c b/src/gprs/gprs_gmm.c
index 358bff9..a18a54e 100644
--- a/src/gprs/gprs_gmm.c
+++ b/src/gprs/gprs_gmm.c
@@ -1616,6 +1616,19 @@
 	}
 }
 
+/* 3GPP TS 24.008 Section 4.7.13.4 Service request procedure not accepted by the
+ * network. Returns true if MS has active PDP contexts in pdp_status */
+bool pdp_status_has_active_nsapis(const uint8_t *pdp_status, const size_t pdp_status_len)
+{
+	size_t i;
+
+	for (i = 0; i < pdp_status_len; i++)
+		if (pdp_status[i] != 0)
+			return true;
+
+	return false;
+}
+
 /* Chapter 9.4.14: Routing area update request */
 static int gsm48_rx_gmm_ra_upd_req(struct sgsn_mm_ctx *mmctx, struct msgb *msg,
 				   struct gprs_llc_llme *llme)
@@ -1896,12 +1909,23 @@
 
 	ctx->iu.service.type = service_type;
 
-	/* TODO: Handle those only in case of accept? */
 	/* Look at PDP Context Status IE and see if MS's view of
 	 * activated/deactivated NSAPIs agrees with our view */
 	if (TLVP_PRESENT(&tp, GSM48_IE_GMM_PDP_CTX_STATUS)) {
 		const uint8_t *pdp_status = TLVP_VAL(&tp, GSM48_IE_GMM_PDP_CTX_STATUS);
+		const size_t pdp_status_len = TLVP_LEN(&tp, GSM48_IE_GMM_PDP_CTX_STATUS);
+
 		process_ms_ctx_status(ctx, pdp_status);
+
+		/* 3GPP TS 24.008 Section 4.7.13.4 Service request procedure not
+		 * accepted by the network. Cause #40. If MS has PDP Contexts in
+		 * Active state in pdp_status but there is no PDP contexts on
+		 * SGSN side then Reject with the cause will force the mobile to
+		 * reset PDP contexts */
+		if (llist_empty(&ctx->pdp_list) && pdp_status_has_active_nsapis(pdp_status, pdp_status_len)) {
+			reject_cause = GMM_CAUSE_NO_PDP_ACTIVATED;
+			goto rejected;
+		}
 	}
 
 
diff --git a/tests/sgsn/sgsn_test.c b/tests/sgsn/sgsn_test.c
index 6145206..23cb4fb 100644
--- a/tests/sgsn/sgsn_test.c
+++ b/tests/sgsn/sgsn_test.c
@@ -1575,6 +1575,22 @@
 	cleanup_test();
 }
 
+bool pdp_status_has_active_nsapis(const uint8_t *pdp_status, const size_t pdp_status_len);
+
+static void test_pdp_status_has_active_nsapis(void)
+{
+	const size_t pdp_status_len = 2;
+	const uint8_t pdp_status1[] = { 0b00100000, 0b00000000 }; /* PDP NSAPI 5 active */
+	const uint8_t pdp_status2[] = { 0b00000000, 0b00000000 }; /* no active PDP NSAPI */
+	const uint8_t pdp_status3[] = { 0b00000000, 0b00000001 }; /* PDP NSAPI 8 active */
+
+	printf("Testing pdp_status_has_active_nsapis\n");
+
+	OSMO_ASSERT(pdp_status_has_active_nsapis(pdp_status1, pdp_status_len));
+	OSMO_ASSERT(!pdp_status_has_active_nsapis(pdp_status2, pdp_status_len));
+	OSMO_ASSERT(pdp_status_has_active_nsapis(pdp_status3, pdp_status_len));
+}
+
 static struct log_info_cat gprs_categories[] = {
 	[DMM] = {
 		.name = "DMM",
@@ -1657,6 +1673,7 @@
 	test_gmm_cancel();
 	test_apn_matching();
 	test_ggsn_selection();
+	test_pdp_status_has_active_nsapis();
 	printf("Done\n");
 
 	talloc_report_full(osmo_sgsn_ctx, stderr);
diff --git a/tests/sgsn/sgsn_test.ok b/tests/sgsn/sgsn_test.ok
index e7e7cf6..35b1d7b 100644
--- a/tests/sgsn/sgsn_test.ok
+++ b/tests/sgsn/sgsn_test.ok
@@ -24,4 +24,5 @@
 Testing cancellation
 Testing APN matching
 Testing GGSN selection
+Testing pdp_status_has_active_nsapis
 Done

-- 
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Gerrit-Project: osmo-sgsn
Gerrit-Branch: master
Gerrit-MessageType: merged
Gerrit-Change-Id: If610cbef17c25ec44e65d4f1b2340d102c560437
Gerrit-Change-Number: 13744
Gerrit-PatchSet: 10
Gerrit-Owner: Mykola Shchetinin <mykola at pentonet.com>
Gerrit-Reviewer: Jenkins Builder (1000002)
Gerrit-Reviewer: Mykola Shchetinin <mykola at pentonet.com>
Gerrit-Reviewer: Pau Espin Pedrol <pespin at sysmocom.de>
Gerrit-Reviewer: lynxis lazus <lynxis at fe80.eu>
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