selftests: bpf: test_lwt_ip_encap: add negative tests.

As requested by David Ahern:

- add negative tests (no routes, explicitly unreachable destinations)
  to exercize error handling code paths;
- do not exit on test failures, but instead print a summary of
  passed/failed tests at the end.

Future patches will add TSO and VRF tests.
Signed-off-by: Peter Oskolkov <posk@google.com>
Reviewed-by: David Ahern <dsahern@gmail.com>
Signed-off-by: Alexei Starovoitov <ast@kernel.org>

tools/testing/selftests/bpf/test_lwt_ip_encap.sh

@@ -38,8 +38,6 @@
 #       ping: SRC->[encap at veth2:ingress]->GRE:decap->DST
 #       ping replies go DST->SRC directly
 
-set -e  # exit on error
-
 if [[ $EUID -ne 0 ]]; then
 	echo "This script must be run as root"
 	echo "FAIL"
@@ -76,8 +74,37 @@ readonly IPv6_GRE="fb10::1"
 readonly IPv6_SRC=$IPv6_1
 readonly IPv6_DST=$IPv6_4
 
-setup() {
-set -e  # exit on error
+TEST_STATUS=0
+TESTS_SUCCEEDED=0
+TESTS_FAILED=0
+
+process_test_results()
+{
+	if [[ "${TEST_STATUS}" -eq 0 ]] ; then
+		echo "PASS"
+		TESTS_SUCCEEDED=$((TESTS_SUCCEEDED+1))
+	else
+		echo "FAIL"
+		TESTS_FAILED=$((TESTS_FAILED+1))
+	fi
+}
+
+print_test_summary_and_exit()
+{
+	echo "passed tests: ${TESTS_SUCCEEDED}"
+	echo "failed tests: ${TESTS_FAILED}"
+	if [ "${TESTS_FAILED}" -eq "0" ] ; then
+		exit 0
+	else
+		exit 1
+	fi
+}
+
+setup()
+{
+	set -e  # exit on error
+	TEST_STATUS=0
+
 	# create devices and namespaces
 	ip netns add "${NS1}"
 	ip netns add "${NS2}"
@@ -178,7 +205,7 @@ set -e  # exit on error
 	# configure IPv4 GRE device in NS3, and a route to it via the "bottom" route
 	ip -netns ${NS3} tunnel add gre_dev mode gre remote ${IPv4_1} local ${IPv4_GRE} ttl 255
 	ip -netns ${NS3} link set gre_dev up
-	ip -netns ${NS3} addr add ${IPv4_GRE} dev gre_dev
+	ip -netns ${NS3} addr add ${IPv4_GRE} nodad dev gre_dev
 	ip -netns ${NS1} route add ${IPv4_GRE}/32 dev veth5 via ${IPv4_6}
 	ip -netns ${NS2} route add ${IPv4_GRE}/32 dev veth7 via ${IPv4_8}
 
@@ -194,9 +221,13 @@ set -e  # exit on error
 	ip netns exec ${NS1} sysctl -wq net.ipv4.conf.all.rp_filter=0
 	ip netns exec ${NS2} sysctl -wq net.ipv4.conf.all.rp_filter=0
 	ip netns exec ${NS3} sysctl -wq net.ipv4.conf.all.rp_filter=0
+
+	sleep 1  # reduce flakiness
+	set +e
 }
 
-cleanup() {
+cleanup()
+{
 	ip netns del ${NS1} 2> /dev/null
 	ip netns del ${NS2} 2> /dev/null
 	ip netns del ${NS3} 2> /dev/null
@@ -204,12 +235,28 @@ cleanup() {
 
 trap cleanup EXIT
 
-test_ping() {
+remove_routes_to_gredev()
+{
+	ip -netns ${NS1} route del ${IPv4_GRE} dev veth5
+	ip -netns ${NS2} route del ${IPv4_GRE} dev veth7
+	ip -netns ${NS1} -6 route del ${IPv6_GRE}/128 dev veth5
+	ip -netns ${NS2} -6 route del ${IPv6_GRE}/128 dev veth7
+}
+
+add_unreachable_routes_to_gredev()
+{
+	ip -netns ${NS1} route add unreachable ${IPv4_GRE}/32
+	ip -netns ${NS2} route add unreachable ${IPv4_GRE}/32
+	ip -netns ${NS1} -6 route add unreachable ${IPv6_GRE}/128
+	ip -netns ${NS2} -6 route add unreachable ${IPv6_GRE}/128
+}
+
+test_ping()
+{
 	local readonly PROTO=$1
 	local readonly EXPECTED=$2
 	local RET=0
 
-	set +e
 	if [ "${PROTO}" == "IPv4" ] ; then
 		ip netns exec ${NS1} ping  -c 1 -W 1 -I ${IPv4_SRC} ${IPv4_DST} 2>&1 > /dev/null
 		RET=$?
@@ -217,29 +264,26 @@ test_ping() {
 		ip netns exec ${NS1} ping6 -c 1 -W 6 -I ${IPv6_SRC} ${IPv6_DST} 2>&1 > /dev/null
 		RET=$?
 	else
-		echo "test_ping: unknown PROTO: ${PROTO}"
-		exit 1
+		echo "    test_ping: unknown PROTO: ${PROTO}"
+		TEST_STATUS=1
 	fi
-	set -e
 
 	if [ "0" != "${RET}" ]; then
 		RET=1
 	fi
 
 	if [ "${EXPECTED}" != "${RET}" ] ; then
-		echo "FAIL: test_ping: ${RET}"
-		exit 1
+		echo "    test_ping failed: expected: ${EXPECTED}; got ${RET}"
+		TEST_STATUS=1
 	fi
 }
 
-test_egress() {
+test_egress()
+{
 	local readonly ENCAP=$1
 	echo "starting egress ${ENCAP} encap test"
 	setup
 
-	# need to wait a bit for IPv6 to autoconf, otherwise
-	# ping6 sometimes fails with "unable to bind to address"
-
 	# by default, pings work
 	test_ping IPv4 0
 	test_ping IPv6 0
@@ -258,16 +302,28 @@ test_egress() {
 		ip -netns ${NS1} route add ${IPv4_DST} encap bpf xmit obj test_lwt_ip_encap.o sec encap_gre6 dev veth1
 		ip -netns ${NS1} -6 route add ${IPv6_DST} encap bpf xmit obj test_lwt_ip_encap.o sec encap_gre6 dev veth1
 	else
-		echo "FAIL: unknown encap ${ENCAP}"
+		echo "    unknown encap ${ENCAP}"
+		TEST_STATUS=1
 	fi
 	test_ping IPv4 0
 	test_ping IPv6 0
 
+	# a negative test: remove routes to GRE devices: ping fails
+	remove_routes_to_gredev
+	test_ping IPv4 1
+	test_ping IPv6 1
+
+	# another negative test
+	add_unreachable_routes_to_gredev
+	test_ping IPv4 1
+	test_ping IPv6 1
+
 	cleanup
-	echo "PASS"
+	process_test_results
 }
 
-test_ingress() {
+test_ingress()
+{
 	local readonly ENCAP=$1
 	echo "starting ingress ${ENCAP} encap test"
 	setup
@@ -298,14 +354,23 @@ test_ingress() {
 	test_ping IPv4 0
 	test_ping IPv6 0
 
+	# a negative test: remove routes to GRE devices: ping fails
+	remove_routes_to_gredev
+	test_ping IPv4 1
+	test_ping IPv6 1
+
+	# another negative test
+	add_unreachable_routes_to_gredev
+	test_ping IPv4 1
+	test_ping IPv6 1
+
 	cleanup
-	echo "PASS"
+	process_test_results
 }
 
 test_egress IPv4
 test_egress IPv6
-
 test_ingress IPv4
 test_ingress IPv6
 
-echo "all tests passed"
+print_test_summary_and_exit