selftests/bpf/test_xdp_redirect: use temp netns for testing

Use temp netns instead of hard code name for testing in case the
netns already exists.
Signed-off-by: Hangbin Liu <liuhangbin@gmail.com>
Acked-by: William Tu <u9012063@gmail.com>
Link: https://lore.kernel.org/r/20220125081717.1260849-8-liuhangbin@gmail.comSigned-off-by: Alexei Starovoitov <ast@kernel.org>

tools/testing/selftests/bpf/test_xdp_redirect.sh

@@ -10,6 +10,8 @@
 #     | xdp forwarding |
 #     ------------------
 
+readonly NS1="ns1-$(mktemp -u XXXXXX)"
+readonly NS2="ns2-$(mktemp -u XXXXXX)"
 ret=0
 
 setup()
@@ -17,27 +19,27 @@ setup()
 
 	local xdpmode=$1
 
-	ip netns add ns1
-	ip netns add ns2
+	ip netns add ${NS1}
+	ip netns add ${NS2}
 
-	ip link add veth1 index 111 type veth peer name veth11 netns ns1
-	ip link add veth2 index 222 type veth peer name veth22 netns ns2
+	ip link add veth1 index 111 type veth peer name veth11 netns ${NS1}
+	ip link add veth2 index 222 type veth peer name veth22 netns ${NS2}
 
 	ip link set veth1 up
 	ip link set veth2 up
-	ip -n ns1 link set dev veth11 up
-	ip -n ns2 link set dev veth22 up
+	ip -n ${NS1} link set dev veth11 up
+	ip -n ${NS2} link set dev veth22 up
 
-	ip -n ns1 addr add 10.1.1.11/24 dev veth11
-	ip -n ns2 addr add 10.1.1.22/24 dev veth22
+	ip -n ${NS1} addr add 10.1.1.11/24 dev veth11
+	ip -n ${NS2} addr add 10.1.1.22/24 dev veth22
 }
 
 cleanup()
 {
 	ip link del veth1 2> /dev/null
 	ip link del veth2 2> /dev/null
-	ip netns del ns1 2> /dev/null
-	ip netns del ns2 2> /dev/null
+	ip netns del ${NS1} 2> /dev/null
+	ip netns del ${NS2} 2> /dev/null
 }
 
 test_xdp_redirect()
@@ -52,13 +54,13 @@ test_xdp_redirect()
 		return 0
 	fi
 
-	ip -n ns1 link set veth11 $xdpmode obj xdp_dummy.o sec xdp &> /dev/null
-	ip -n ns2 link set veth22 $xdpmode obj xdp_dummy.o sec xdp &> /dev/null
+	ip -n ${NS1} link set veth11 $xdpmode obj xdp_dummy.o sec xdp &> /dev/null
+	ip -n ${NS2} link set veth22 $xdpmode obj xdp_dummy.o sec xdp &> /dev/null
 	ip link set dev veth1 $xdpmode obj test_xdp_redirect.o sec redirect_to_222 &> /dev/null
 	ip link set dev veth2 $xdpmode obj test_xdp_redirect.o sec redirect_to_111 &> /dev/null
 
-	if ip netns exec ns1 ping -c 1 10.1.1.22 &> /dev/null &&
-	   ip netns exec ns2 ping -c 1 10.1.1.11 &> /dev/null; then
+	if ip netns exec ${NS1} ping -c 1 10.1.1.22 &> /dev/null &&
+	   ip netns exec ${NS2} ping -c 1 10.1.1.11 &> /dev/null; then
 		echo "selftests: test_xdp_redirect $xdpmode [PASS]";
 	else
 		ret=1