selftests/bpf: bpf tunnel encap test

Validate basic tunnel encapsulation using ipip.

Set up two namespaces connected by veth. Connect a client and server.
Do this with and without bpf encap.

Signed-off-by: Willem de Bruijn <willemb@google.com>
Signed-off-by: Alexei Starovoitov <ast@kernel.org>

1 files changed, 75 insertions, 0 deletions

diff --git a/tools/testing/selftests/bpf/test_tc_tunnel.sh b/tools/testing/selftests/bpf/test_tc_tunnel.sh
new file mode 100755
index 000000000000..6ebb288a3afc
--- /dev/null
+++ b/tools/testing/selftests/bpf/test_tc_tunnel.sh
@@ -0,0 +1,75 @@
+#!/bin/bash
+# SPDX-License-Identifier: GPL-2.0
+#
+# In-place tunneling
+
+# must match the port that the bpf program filters on
+readonly port=8000
+
+readonly ns_prefix="ns-$$-"
+readonly ns1="${ns_prefix}1"
+readonly ns2="${ns_prefix}2"
+
+readonly ns1_v4=192.168.1.1
+readonly ns2_v4=192.168.1.2
+
+setup() {
+	ip netns add "${ns1}"
+	ip netns add "${ns2}"
+
+	ip link add dev veth1 mtu 1500 netns "${ns1}" type veth \
+	      peer name veth2 mtu 1500 netns "${ns2}"
+
+	ip -netns "${ns1}" link set veth1 up
+	ip -netns "${ns2}" link set veth2 up
+
+	ip -netns "${ns1}" -4 addr add "${ns1_v4}/24" dev veth1
+	ip -netns "${ns2}" -4 addr add "${ns2_v4}/24" dev veth2
+
+	sleep 1
+}
+
+cleanup() {
+	ip netns del "${ns2}"
+	ip netns del "${ns1}"
+}
+
+server_listen() {
+	ip netns exec "${ns2}" nc -l -p "${port}" &
+	sleep 0.2
+}
+
+client_connect() {
+	ip netns exec "${ns1}" nc -z -w 1 "${ns2_v4}" "${port}"
+	echo $?
+}
+
+set -e
+trap cleanup EXIT
+
+setup
+
+# basic communication works
+echo "test basic connectivity"
+server_listen
+client_connect
+
+# clientside, insert bpf program to encap all TCP to port ${port}
+# client can no longer connect
+ip netns exec "${ns1}" tc qdisc add dev veth1 clsact
+ip netns exec "${ns1}" tc filter add dev veth1 egress \
+	bpf direct-action object-file ./test_tc_tunnel.o section encap
+echo "test bpf encap without decap (expect failure)"
+server_listen
+! client_connect
+
+# serverside, insert decap module
+# server is still running
+# client can connect again
+ip netns exec "${ns2}" ip link add dev testtun0 type ipip \
+	remote "${ns1_v4}" local "${ns2_v4}"
+ip netns exec "${ns2}" ip link set dev testtun0 up
+echo "test bpf encap with tunnel device decap"
+client_connect
+
+echo OK