new file mode 100755
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+#!/bin/bash
+# SPDX-License-Identifier: GPL-2.0
+
+# Test IP-in-IP GRE tunnel with key.
+# This test uses flat topology for IP tunneling tests. See ipip_lib.sh for more
+# details.
+
+ALL_TESTS="gre_flat4 gre_mtu_change"
+
+NUM_NETIFS=6
+source lib.sh
+source ipip_lib.sh
+
+setup_prepare()
+{
+ h1=${NETIFS[p1]}
+ ol1=${NETIFS[p2]}
+
+ ul1=${NETIFS[p3]}
+ ul2=${NETIFS[p4]}
+
+ ol2=${NETIFS[p5]}
+ h2=${NETIFS[p6]}
+
+ forwarding_enable
+ vrf_prepare
+ h1_create
+ h2_create
+ sw1_flat_create gre $ol1 $ul1 ikey 111 okey 222
+ sw2_flat_create gre $ol2 $ul2 ikey 222 okey 111
+}
+
+gre_flat4()
+{
+ RET=0
+
+ ping_test $h1 192.0.2.18 " gre flat with ikey/okey"
+}
+
+gre_mtu_change()
+{
+ test_mtu_change gre
+}
+
+cleanup()
+{
+ pre_cleanup
+
+ sw2_flat_destroy $ol2 $ul2
+ sw1_flat_destroy $ol1 $ul1
+ h2_destroy
+ h1_destroy
+ vrf_cleanup
+ forwarding_restore
+}
+
+trap cleanup EXIT
+
+setup_prepare
+setup_wait
+tests_run
+
+exit $EXIT_STATUS