netdev - [PATCH net 2/2] selftests: pmtu: add explicit tests for pmtu exceptions cleanup

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Date:   Fri, 22 Feb 2019 17:06:33 +0100
From:   Paolo Abeni <pabeni@...hat.com>
To:     netdev@...r.kernel.org
Cc:     "David S. Miller" <davem@...emloft.net>,
        David Ahern <dsahern@...il.com>,
        Stefano Brivio <sbrivio@...hat.com>
Subject: [PATCH net 2/2] selftests: pmtu: add explicit tests for pmtu exceptions cleanup

Add a couple of new tests, explicitly checking that the kernel
timely releases pmtu exceptions on related device removal.
This is mostly a regression test vs the issue fixed by:
https://patchwork.ozlabs.org/patch/1045488/

Only 2 new test cases have been added, instead of extending all
the existing ones, because the reproducer requires executing
several commands and would slow down too much the tests otherwise.

Signed-off-by: Paolo Abeni <pabeni@...hat.com>
---
 tools/testing/selftests/net/pmtu.sh | 52 ++++++++++++++++++++++++++++-
 1 file changed, 51 insertions(+), 1 deletion(-)

diff --git a/tools/testing/selftests/net/pmtu.sh b/tools/testing/selftests/net/pmtu.sh
index 634e91e8fe25..4bc72bc26899 100755
--- a/tools/testing/selftests/net/pmtu.sh
+++ b/tools/testing/selftests/net/pmtu.sh
@@ -135,7 +135,9 @@ tests="
 	pmtu_vti6_default_mtu		vti6: default MTU assignment
 	pmtu_vti4_link_add_mtu		vti4: MTU setting on link creation
 	pmtu_vti6_link_add_mtu		vti6: MTU setting on link creation
-	pmtu_vti6_link_change_mtu	vti6: MTU changes on link changes"
+	pmtu_vti6_link_change_mtu	vti6: MTU changes on link changes
+	pmtu_ipv4_exception_cleanup	ipv4: cleanup of cached exceptions
+	pmtu_ipv6_exception_cleanup	ipv6: cleanup of cached exceptions"
 
 NS_A="ns-$(mktemp -u XXXXXX)"
 NS_B="ns-$(mktemp -u XXXXXX)"
@@ -1006,6 +1008,54 @@ test_pmtu_vti6_link_change_mtu() {
 	return ${fail}
 }
 
+test_cleanup_vxlanY_or_geneveY_exception() {
+	outer="${1}"
+	encap="${2}"
+	ll_mtu=4000
+
+	which taskset 2>/dev/null | return 2
+	which timeout 2>/dev/null | return 2
+	cpu_list=`grep processor /proc/cpuinfo | cut -d ' ' -f 2`
+
+	setup namespaces routing ${encap}${outer} || return 2
+	trace "${ns_a}" ${encap}_a   "${ns_b}"  ${encap}_b \
+	      "${ns_a}" veth_A-R1    "${ns_r1}" veth_R1-A \
+	      "${ns_b}" veth_B-R1    "${ns_r1}" veth_R1-B
+
+	# Create route exception by exceeding link layer MTU
+	mtu "${ns_a}"  veth_A-R1 $((${ll_mtu} + 1000))
+	mtu "${ns_r1}" veth_R1-A $((${ll_mtu} + 1000))
+	mtu "${ns_b}"  veth_B-R1 ${ll_mtu}
+	mtu "${ns_r1}" veth_R1-B ${ll_mtu}
+
+	mtu "${ns_a}" ${encap}_a $((${ll_mtu} + 1000))
+	mtu "${ns_b}" ${encap}_b $((${ll_mtu} + 1000))
+
+	# fill exception cache for multiple cpus [2]
+	# we can always use inner ipv4 for that
+	ncpus=0
+	for cpu in $cpu_list; do
+		taskset --cpu-list ${cpu} ${ns_a} ping -q -M want -i 0.1 -w 1 -s $((${ll_mtu} + 500)) ${tunnel4_b_addr} > /dev/null
+		ncpus=$((ncpus + 1))
+		[ ${ncpus} -gt 1 ] && break
+	done
+
+	fail=0
+	if ! timeout 1 ${ns_a} ip link del dev veth_A-R1; then
+		err "  can't delete veth device in a timely manner, pmtu dst likely leaked"
+		fail=1
+	fi
+	return ${fail}
+}
+
+test_pmtu_ipv6_exception_cleanup() {
+	test_cleanup_vxlanY_or_geneveY_exception 6 vxlan
+}
+
+test_pmtu_ipv4_exception_cleanup() {
+	test_cleanup_vxlanY_or_geneveY_exception 4 vxlan
+}
+
 usage() {
 	echo
 	echo "$0 [OPTIONS] [TEST]..."
-- 
2.20.1