selftests: add selftest for chaining of tc ingress handling to egress

This test runs a simple ingress tc setup between two veth pairs,
then adds a egress->ingress rule to test the chaining of tc ingress
pipeline to tc egress piepline.

Signed-off-by: Paul Blakey <paulb@nvidia.com>
Signed-off-by: David S. Miller <davem@davemloft.net>

tools/testing/selftests/net/Makefile

@@ -70,6 +70,7 @@ TEST_PROGS += io_uring_zerocopy_tx.sh
 TEST_GEN_FILES += bind_bhash
 TEST_GEN_PROGS += sk_bind_sendto_listen
 TEST_GEN_PROGS += sk_connect_zero_addr
+TEST_PROGS += test_ingress_egress_chaining.sh
 
 TEST_FILES := settings
 

tools/testing/selftests/net/test_ingress_egress_chaining.sh

@@ -0,0 +1,79 @@
+#!/bin/bash
+# SPDX-License-Identifier: GPL-2.0
+
+# This test runs a simple ingress tc setup between two veth pairs,
+# and chains a single egress rule to test ingress chaining to egress.
+#
+# Kselftest framework requirement - SKIP code is 4.
+ksft_skip=4
+
+if [ "$(id -u)" -ne 0 ];then
+	echo "SKIP: Need root privileges"
+	exit $ksft_skip
+fi
+
+needed_mods="act_mirred cls_flower sch_ingress"
+for mod in $needed_mods; do
+	modinfo $mod &>/dev/null || { echo "SKIP: Need act_mirred module"; exit $ksft_skip; }
+done
+
+ns="ns$((RANDOM%899+100))"
+veth1="veth1$((RANDOM%899+100))"
+veth2="veth2$((RANDOM%899+100))"
+peer1="peer1$((RANDOM%899+100))"
+peer2="peer2$((RANDOM%899+100))"
+ip_peer1=198.51.100.5
+ip_peer2=198.51.100.6
+
+function fail() {
+	echo "FAIL: $@" >> /dev/stderr
+	exit 1
+}
+
+function cleanup() {
+	killall -q -9 udpgso_bench_rx
+	ip link del $veth1 &> /dev/null
+	ip link del $veth2 &> /dev/null
+	ip netns del $ns &> /dev/null
+}
+trap cleanup EXIT
+
+function config() {
+	echo "Setup veth pairs [$veth1, $peer1], and veth pair [$veth2, $peer2]"
+	ip link add $veth1 type veth peer name $peer1
+	ip link add $veth2 type veth peer name $peer2
+	ip addr add $ip_peer1/24 dev $peer1
+	ip link set $peer1 up
+	ip netns add $ns
+	ip link set dev $peer2 netns $ns
+	ip netns exec $ns ip addr add $ip_peer2/24 dev $peer2
+	ip netns exec $ns ip link set $peer2 up
+	ip link set $veth1 up
+	ip link set $veth2 up
+
+	echo "Add tc filter ingress->egress forwarding $veth1 <-> $veth2"
+	tc qdisc add dev $veth2 ingress
+	tc qdisc add dev $veth1 ingress
+	tc filter add dev $veth2 ingress prio 1 proto all flower \
+		action mirred egress redirect dev $veth1
+	tc filter add dev $veth1 ingress prio 1 proto all flower \
+		action mirred egress redirect dev $veth2
+
+	echo "Add tc filter egress->ingress forwarding $peer1 -> $veth1, bypassing the veth pipe"
+	tc qdisc add dev $peer1 clsact
+	tc filter add dev $peer1 egress prio 20 proto ip flower \
+		action mirred ingress redirect dev $veth1
+}
+
+function test_run() {
+	echo "Run tcp traffic"
+	./udpgso_bench_rx -t &
+	sleep 1
+	ip netns exec $ns timeout -k 2 10 ./udpgso_bench_tx -t -l 2 -4 -D $ip_peer1 || fail "traffic failed"
+	echo "Test passed"
+}
+
+config
+test_run
+trap - EXIT
+cleanup