selftests/net: convert arp_ndisc_untracked_subnets.sh to run it in unique namespace

Here is the test result after conversion.

2 tests also failed without this patch

]# ./arp_ndisc_untracked_subnets.sh
    TEST: test_arp:  accept_arp=0                                       [ OK ]
    TEST: test_arp:  accept_arp=1                                       [ OK ]
    TEST: test_arp:  accept_arp=2  same_subnet=0                        [ OK ]
    TEST: test_arp:  accept_arp=2  same_subnet=1                        [ OK ]
    TEST: test_ndisc:  accept_untracked_na=0                            [ OK ]
    TEST: test_ndisc:  accept_untracked_na=1                            [ OK ]
    TEST: test_ndisc:  accept_untracked_na=2  same_subnet=0             [ OK ]
    TEST: test_ndisc:  accept_untracked_na=2  same_subnet=1             [ OK ]
Acked-by: David Ahern <dsahern@kernel.org>
Signed-off-by: Hangbin Liu <liuhangbin@gmail.com>
Signed-off-by: Paolo Abeni <pabeni@redhat.com>

tools/testing/selftests/net/arp_ndisc_untracked_subnets.sh

@@ -5,16 +5,14 @@
 # garp to the router. Router accepts or ignores based on its arp_accept
 # or accept_untracked_na configuration.
 
+source lib.sh
+
 TESTS="arp ndisc"
 
-ROUTER_NS="ns-router"
-ROUTER_NS_V6="ns-router-v6"
 ROUTER_INTF="veth-router"
 ROUTER_ADDR="10.0.10.1"
 ROUTER_ADDR_V6="2001:db8:abcd:0012::1"
 
-HOST_NS="ns-host"
-HOST_NS_V6="ns-host-v6"
 HOST_INTF="veth-host"
 HOST_ADDR="10.0.10.2"
 HOST_ADDR_V6="2001:db8:abcd:0012::2"
@@ -23,13 +21,11 @@ SUBNET_WIDTH=24
 PREFIX_WIDTH_V6=64
 
 cleanup() {
-	ip netns del ${HOST_NS}
-	ip netns del ${ROUTER_NS}
+	cleanup_ns ${HOST_NS} ${ROUTER_NS}
 }
 
 cleanup_v6() {
-	ip netns del ${HOST_NS_V6}
-	ip netns del ${ROUTER_NS_V6}
+	cleanup_ns ${HOST_NS_V6} ${ROUTER_NS_V6}
 }
 
 setup() {
@@ -37,8 +33,7 @@ setup() {
 	local arp_accept=$1
 
 	# Set up two namespaces
-	ip netns add ${ROUTER_NS}
-	ip netns add ${HOST_NS}
+	setup_ns HOST_NS ROUTER_NS
 
 	# Set up interfaces veth0 and veth1, which are pairs in separate
 	# namespaces. veth0 is veth-router, veth1 is veth-host.
@@ -72,8 +67,7 @@ setup_v6() {
 	local accept_untracked_na=$1
 
 	# Set up two namespaces
-	ip netns add ${ROUTER_NS_V6}
-	ip netns add ${HOST_NS_V6}
+	setup_ns HOST_NS_V6 ROUTER_NS_V6
 
 	# Set up interfaces veth0 and veth1, which are pairs in separate
 	# namespaces. veth0 is veth-router, veth1 is veth-host.