ggsn: Validate IPCP identifier in answer matches the one in the request

Related: https://github.com/open5gs/open5gs/pull/2920
Related: SYS#6582
Change-Id: I0e0cefaeb303b4e284173011231170554e225561
diff --git a/library/GTP_Templates.ttcn b/library/GTP_Templates.ttcn
index 3788725..30346d4 100644
--- a/library/GTP_Templates.ttcn
+++ b/library/GTP_Templates.ttcn
@@ -973,13 +973,13 @@
 		}
 	}
 
-	template (value) ProtConfigOptions ts_PCO_IPv4_DNS_IPCP modifies ts_PCO := {
+	template (value) ProtConfigOptions ts_PCO_IPv4_DNS_IPCP(uint8_t ipcp_req_id := 0) modifies ts_PCO := {
 		protocols := {
 			/* dummy PAP entry to check if our parser in the GGSN can properly iterate over
 			 * the list of protocols, see Change-Id Icc2e6716c33d78d3c3e000f529806228d8aa155e */
 			{ protocolID := 'C023'O, lengthProtoID := 0, protoIDContents := ''O },
 			{ protocolID := '8021'O, lengthProtoID := 16, protoIDContents :=
-								enc_IpcpPacket(valueof(ts_IPCP_ReqDNS)) }
+								enc_IpcpPacket(valueof(ts_IPCP_ReqDNS(ipcp_req_id))) }
 		}
 	}