selftests: fib_tests: Add a test case for IPv6 garbage collection

Add 1000 IPv6 routes with expiration time (w/ and w/o additional 5000
permanet routes in the background.)  Wait for a few seconds to make sure
they are removed correctly.

The expected output of the test looks like the following example.

> Fib6 garbage collection test
>     TEST: ipv6 route garbage collection [ OK ]
Signed-off-by: Kui-Feng Lee <thinker.li@gmail.com>
Reviewed-by: David Ahern <dsahern@kernel.org>
Signed-off-by: David S. Miller <davem@davemloft.net>

tools/testing/selftests/net/fib_tests.sh

@@ -9,13 +9,16 @@ ret=0
 ksft_skip=4
 
 # all tests in this script. Can be overridden with -t option
-TESTS="unregister down carrier nexthop suppress ipv6_notify ipv4_notify ipv6_rt ipv4_rt ipv6_addr_metric ipv4_addr_metric ipv6_route_metrics ipv4_route_metrics ipv4_route_v6_gw rp_filter ipv4_del_addr ipv4_mangle ipv6_mangle ipv4_bcast_neigh"
+TESTS="unregister down carrier nexthop suppress ipv6_notify ipv4_notify \
+       ipv6_rt ipv4_rt ipv6_addr_metric ipv4_addr_metric ipv6_route_metrics \
+       ipv4_route_metrics ipv4_route_v6_gw rp_filter ipv4_del_addr \
+       ipv4_mangle ipv6_mangle ipv4_bcast_neigh fib6_gc_test"
 
 VERBOSE=0
 PAUSE_ON_FAIL=no
 PAUSE=no
-IP="ip -netns ns1"
-NS_EXEC="ip netns exec ns1"
+IP="$(which ip) -netns ns1"
+NS_EXEC="$(which ip) netns exec ns1"
 
 which ping6 > /dev/null 2>&1 && ping6=$(which ping6) || ping6=$(which ping)
 
@@ -747,6 +750,68 @@ fib_notify_test()
 	cleanup &> /dev/null
 }
 
+fib6_gc_test()
+{
+	setup
+
+	echo
+	echo "Fib6 garbage collection test"
+	set -e
+
+	EXPIRE=3
+
+	# Check expiration of routes every $EXPIRE seconds (GC)
+	$NS_EXEC sysctl -wq net.ipv6.route.gc_interval=$EXPIRE
+
+	$IP link add dummy_10 type dummy
+	$IP link set dev dummy_10 up
+	$IP -6 address add 2001:10::1/64 dev dummy_10
+
+	$NS_EXEC sysctl -wq net.ipv6.route.flush=1
+
+	# Temporary routes
+	for i in $(seq 1 1000); do
+	    # Expire route after $EXPIRE seconds
+	    $IP -6 route add 2001:20::$i \
+		via 2001:10::2 dev dummy_10 expires $EXPIRE
+	done
+	sleep $(($EXPIRE * 2))
+	N_EXP_SLEEP=$($IP -6 route list |grep expires|wc -l)
+	if [ $N_EXP_SLEEP -ne 0 ]; then
+	    echo "FAIL: expected 0 routes with expires, got $N_EXP_SLEEP"
+	    ret=1
+	else
+	    ret=0
+	fi
+
+	# Permanent routes
+	for i in $(seq 1 5000); do
+	    $IP -6 route add 2001:30::$i \
+		via 2001:10::2 dev dummy_10
+	done
+	# Temporary routes
+	for i in $(seq 1 1000); do
+	    # Expire route after $EXPIRE seconds
+	    $IP -6 route add 2001:20::$i \
+		via 2001:10::2 dev dummy_10 expires $EXPIRE
+	done
+	sleep $(($EXPIRE * 2))
+	N_EXP_SLEEP=$($IP -6 route list |grep expires|wc -l)
+	if [ $N_EXP_SLEEP -ne 0 ]; then
+	    echo "FAIL: expected 0 routes with expires," \
+		 "got $N_EXP_SLEEP (5000 permanent routes)"
+	    ret=1
+	else
+	    ret=0
+	fi
+
+	set +e
+
+	log_test $ret 0 "ipv6 route garbage collection"
+
+	cleanup &> /dev/null
+}
+
 fib_suppress_test()
 {
 	echo
@@ -2217,6 +2282,7 @@ do
 	ipv4_mangle)			ipv4_mangle_test;;
 	ipv6_mangle)			ipv6_mangle_test;;
 	ipv4_bcast_neigh)		ipv4_bcast_neigh_test;;
+	fib6_gc_test|ipv6_gc)		fib6_gc_test;;
 
 	help) echo "Test names: $TESTS"; exit 0;;
 	esac