asterisk: IMS: Fix seq_nr during MT calls

Change-Id: Ieeb9fb803ab3b1d02b5bfd8198702780914ec318
---
M asterisk/IMS_ConnectionHandler.ttcn
1 file changed, 17 insertions(+), 6 deletions(-)

diff --git a/asterisk/IMS_ConnectionHandler.ttcn b/asterisk/IMS_ConnectionHandler.ttcn
index 4b50c31..c7d87b2 100644
--- a/asterisk/IMS_ConnectionHandler.ttcn
+++ b/asterisk/IMS_ConnectionHandler.ttcn
@@ -1128,6 +1128,7 @@
 	var default d_trying, d_ringing;
 	var charstring branch_value;
 	var Contact calling_contact, called_contact;
+	var integer sip_seq_nr;
 
 	/* RFC 3261 8.1.1.3 From */
 	g_pars.subscr.cp.from_addr := valueof(ts_From(g_pars.subscr.cp.calling.addr, g_pars.subscr.cp.calling.params));
@@ -1168,12 +1169,13 @@
 		supported := ts_Supported(supported_list);
 	}
 
+	sip_seq_nr := g_pars.subscr.cp.sip_seq_nr;
 	req := ts_SIP_INVITE(g_pars.subscr.cp.sip_call_id,
 			     g_pars.subscr.cp.from_addr,
 			     g_pars.subscr.cp.to_addr,
 			     via,
 			     calling_contact,
-			     g_pars.subscr.cp.sip_seq_nr,
+			     sip_seq_nr,
 			     accept := ts_Accept({ ts_AcceptBody("application/sdp"), ts_AcceptBody("application/3gpp-ims+xml") }),
 			     min_SE := min_SE,
 			     session_expires := session_expires,
@@ -1187,7 +1189,7 @@
 			from_addr_exp,
 			to_addr_exp,
 			f_tr_Via_response(via),
-			g_pars.subscr.cp.sip_seq_nr, "INVITE");
+			sip_seq_nr, "INVITE");
 	d_trying := activate(as_SIP_ignore_resp(exp));
 
 	if (g_pars.subscr.cp.mt.tx_coord_cmd_session_progress) {
@@ -1203,7 +1205,7 @@
 				from_addr_exp,
 				to_addr_exp,
 				f_tr_Via_response(via),
-				g_pars.subscr.cp.sip_seq_nr, "INVITE",
+				sip_seq_nr, "INVITE",
 				require := tr_Require(superset("100rel", "precondition")),
 				rseq := tr_RSeq(?),
 				body := ?);
@@ -1310,13 +1312,14 @@
 
 		g_pars.subscr.cp.sip_seq_nr := g_rx_sip_resp.msgHeader.cSeq.seqNumber + 1;
 	}
+	g_pars.subscr.cp.sip_seq_nr := g_pars.subscr.cp.sip_seq_nr + 1;
 
 	/* Conditionally match and accept 180 Ringing */
 	exp := tr_SIP_Response_Ringing(g_pars.subscr.cp.sip_call_id,
 			from_addr_exp,
 			to_addr_exp,
 			f_tr_Via_response(via),
-			g_pars.subscr.cp.sip_seq_nr, "INVITE");
+			sip_seq_nr, "INVITE");
 	d_ringing := activate(as_SIP_ignore_resp(exp));
 
 	called_contact := g_rx_sip_resp.msgHeader.contact;
@@ -1329,7 +1332,7 @@
 			f_tr_Via_response(via),
 			called_contact,
 			"INVITE", 200,
-			g_pars.subscr.cp.sip_seq_nr, "OK",
+			sip_seq_nr, "OK",
 			body := *);
 	as_SIP_expect_resp(exp, fail_others := false);
 
@@ -1343,7 +1346,6 @@
 	g_pars.subscr.cp.to_addr := g_rx_sip_resp.msgHeader.toField;
 
 	/* Transmit ACK */
-	g_pars.subscr.cp.sip_seq_nr := g_pars.subscr.cp.sip_seq_nr + 1;
 	req := ts_SIP_ACK(called_contact.contactBody.contactAddresses[0].addressField.nameAddr.addrSpec,
 			  g_pars.subscr.cp.sip_call_id,
 			  g_pars.subscr.cp.from_addr,

