gprs_ns2_sns: free the NSE if the SIZE PDU is not valid

The SGSN fsm should be freed when becoming invalid instead of going
into the unconfigured state. The unconfigured states should be only used
when creating the NSE (on the SGSN side).

Change-Id: Ife889091ecba4180a90743deb786767008fe863d
diff --git a/src/gb/gprs_ns2_sns.c b/src/gb/gprs_ns2_sns.c
index 5e43d8c..a9ace5f 100644
--- a/src/gb/gprs_ns2_sns.c
+++ b/src/gb/gprs_ns2_sns.c
@@ -2246,12 +2246,16 @@
 		    !TLVP_PRES_LEN(tp, NS_IE_MAX_NR_NSVC, 2)) {
 			cause = NS_CAUSE_MISSING_ESSENT_IE;
 			ns2_tx_sns_size_ack(gss->sns_nsvc, &cause);
+			if (fi->state == GPRS_SNS_ST_UNCONFIGURED)
+				sns_failed(fi, "Rx Size: Missing essential IE");
 			break;
 		}
 		if (!TLVP_PRES_LEN(tp, NS_IE_IPv4_EP_NR, 2) &&
 		    !TLVP_PRES_LEN(tp, NS_IE_IPv6_EP_NR, 2)) {
 			cause = NS_CAUSE_MISSING_ESSENT_IE;
 			ns2_tx_sns_size_ack(gss->sns_nsvc, &cause);
+			if (fi->state == GPRS_SNS_ST_UNCONFIGURED)
+				sns_failed(fi, "Rx Size: Missing essential IE");
 			break;
 		}
 		if (TLVP_PRES_LEN(tp, NS_IE_IPv4_EP_NR, 2))
@@ -2275,6 +2279,8 @@
 			else
 				cause = NS_CAUSE_INVAL_NR_IPv6_EP;
 			ns2_tx_sns_size_ack(gss->sns_nsvc, &cause);
+			if (fi->state == GPRS_SNS_ST_UNCONFIGURED)
+				sns_failed(fi, "Rx Size: Invalid Nr of IPv4/IPv6 EPs");
 			break;
 		}
 		/* ensure number of NS-VCs is sufficient for full mesh */
@@ -2285,6 +2291,8 @@
 				 num_remote_eps, num_local_eps * num_remote_eps, gss->num_max_nsvcs);
 			cause = NS_CAUSE_INVAL_NR_NS_VC;
 			ns2_tx_sns_size_ack(gss->sns_nsvc, &cause);
+			if (fi->state == GPRS_SNS_ST_UNCONFIGURED)
+				sns_failed(fi, NULL);
 			break;
 		}
 		/* perform state reset, if requested */
@@ -2309,6 +2317,12 @@
 			}
 			ns2_sns_compute_local_ep_from_binds(fi);
 		}
+
+		if (fi->state == GPRS_SNS_ST_UNCONFIGURED && !(flag & 1)) {
+			sns_failed(fi, "Rx Size without Reset flag, but NSE is unknown");
+			break;
+		}
+
 		/* send SIZE_ACK */
 		ns2_tx_sns_size_ack(gss->sns_nsvc, NULL);
 		/* only wait for SNS-CONFIG in case of Reset flag */