selftests: pmtu: Introduce list_flush_ipv6_exception test case

This test checks that route exceptions can be successfully listed and
flushed using ip -6 route {list,flush} cache.
Signed-off-by: NStefano Brivio <sbrivio@redhat.com>
Signed-off-by: NDavid S. Miller <davem@davemloft.net>

tools/testing/selftests/net/pmtu.sh

@@ -111,6 +111,10 @@
 #
 # - cleanup_ipv6_exception
 #	Same as above, but use IPv6 transport from A to B
+#
+# - list_flush_ipv6_exception
+#	Using the same topology as in pmtu_ipv6, create exceptions, and check
+#	they are shown when listing exception caches, gone after flushing them
 
 
 # Kselftest framework requirement - SKIP code is 4.
@@ -151,7 +155,8 @@ tests="
 	pmtu_vti6_link_add_mtu		vti6: MTU setting on link creation	0
 	pmtu_vti6_link_change_mtu	vti6: MTU changes on link changes	0
 	cleanup_ipv4_exception		ipv4: cleanup of cached exceptions	1
-	cleanup_ipv6_exception		ipv6: cleanup of cached exceptions	1"
+	cleanup_ipv6_exception		ipv6: cleanup of cached exceptions	1
+	list_flush_ipv6_exception	ipv6: list and flush cached exceptions	1"
 
 NS_A="ns-A"
 NS_B="ns-B"
@@ -1202,6 +1207,50 @@ run_test_nh() {
 	USE_NH=no
 }
 
+test_list_flush_ipv6_exception() {
+	setup namespaces routing || return 2
+	trace "${ns_a}"  veth_A-R1    "${ns_r1}" veth_R1-A \
+	      "${ns_r1}" veth_R1-B    "${ns_b}"  veth_B-R1 \
+	      "${ns_a}"  veth_A-R2    "${ns_r2}" veth_R2-A \
+	      "${ns_r2}" veth_R2-B    "${ns_b}"  veth_B-R2
+
+	dst1="${prefix6}:${b_r1}::1"
+	dst2="${prefix6}:${b_r2}::1"
+
+	# Set up initial MTU values
+	mtu "${ns_a}"  veth_A-R1 2000
+	mtu "${ns_r1}" veth_R1-A 2000
+	mtu "${ns_r1}" veth_R1-B 1500
+	mtu "${ns_b}"  veth_B-R1 1500
+
+	mtu "${ns_a}"  veth_A-R2 2000
+	mtu "${ns_r2}" veth_R2-A 2000
+	mtu "${ns_r2}" veth_R2-B 1500
+	mtu "${ns_b}"  veth_B-R2 1500
+
+	fail=0
+
+	# Create route exceptions
+	run_cmd ${ns_a} ${ping6} -q -M want -i 0.1 -w 1 -s 1800 ${dst1}
+	run_cmd ${ns_a} ${ping6} -q -M want -i 0.1 -w 1 -s 1800 ${dst2}
+
+	if [ "$(${ns_a} ip -6 route list cache | wc -l)" -ne 2 ]; then
+		err "  can't list cached exceptions"
+		fail=1
+	fi
+
+	run_cmd ${ns_a} ip -6 route flush cache
+	sleep 1
+	pmtu1="$(route_get_dst_pmtu_from_exception "${ns_a}" ${dst1})"
+	pmtu2="$(route_get_dst_pmtu_from_exception "${ns_a}" ${dst2})"
+	if [ -n "${pmtu1}" ] || [ -n "${pmtu2}" ]; then
+		err "  can't flush cached exceptions"
+		fail=1
+	fi
+
+	return ${fail}
+}
+
 usage() {
 	echo
 	echo "$0 [OPTIONS] [TEST]..."