selftests: mlxsw: Add a test for blackhole routes

Use a simple topology consisting of two hosts directly connected to a
router. Make sure IPv4/IPv6 ping works and then add blackhole routes.
Test that ping fails and that the routes are marked as offloaded. Use a
simple tc filter to test that packets were dropped by the ASIC and not
trapped to the CPU.
Signed-off-by: Ido Schimmel <idosch@mellanox.com>
Signed-off-by: David S. Miller <davem@davemloft.net>

tools/testing/selftests/drivers/net/mlxsw/blackhole_routes.sh

+#!/bin/bash
+# SPDX-License-Identifier: GPL-2.0
+#
+# Test that blackhole routes are marked as offloaded and that packets hitting
+# them are dropped by the ASIC and not by the kernel.
+#
+# +---------------------------------+
+# | H1 (vrf)                        |
+# |    + $h1                        |
+# |    | 192.0.2.1/24               |
+# |    | 2001:db8:1::1/64           |
+# |    |                            |
+# |    |  default via 192.0.2.2     |
+# |    |  default via 2001:db8:1::2 |
+# +----|----------------------------+
+#      |
+# +----|----------------------------------------------------------------------+
+# | SW |                                                                      |
+# |    + $rp1                                                                 |
+# |        192.0.2.2/24                                                       |
+# |        2001:db8:1::2/64                                                   |
+# |                                                                           |
+# |        2001:db8:2::2/64                                                   |
+# |        198.51.100.2/24                                                    |
+# |    + $rp2                                                                 |
+# |    |                                                                      |
+# +----|----------------------------------------------------------------------+
+#      |
+# +----|----------------------------+
+# |    |  default via 198.51.100.2  |
+# |    |  default via 2001:db8:2::2 |
+# |    |                            |
+# |    | 2001:db8:2::1/64           |
+# |    | 198.51.100.1/24            |
+# |    + $h2                        |
+# | H2 (vrf)                        |
+# +---------------------------------+
+
+lib_dir=$(dirname $0)/../../../net/forwarding
+
+ALL_TESTS="
+	ping_ipv4
+	ping_ipv6
+	blackhole_ipv4
+	blackhole_ipv6
+"
+NUM_NETIFS=4
+source $lib_dir/tc_common.sh
+source $lib_dir/lib.sh
+
+h1_create()
+{
+	simple_if_init $h1 192.0.2.1/24 2001:db8:1::1/64
+
+	ip -4 route add default vrf v$h1 nexthop via 192.0.2.2
+	ip -6 route add default vrf v$h1 nexthop via 2001:db8:1::2
+}
+
+h1_destroy()
+{
+	ip -6 route del default vrf v$h1 nexthop via 2001:db8:1::2
+	ip -4 route del default vrf v$h1 nexthop via 192.0.2.2
+
+	simple_if_fini $h1 192.0.2.1/24 2001:db8:1::1/64
+}
+
+h2_create()
+{
+	simple_if_init $h2 198.51.100.1/24 2001:db8:2::1/64
+
+	ip -4 route add default vrf v$h2 nexthop via 198.51.100.2
+	ip -6 route add default vrf v$h2 nexthop via 2001:db8:2::2
+}
+
+h2_destroy()
+{
+	ip -6 route del default vrf v$h2 nexthop via 2001:db8:2::2
+	ip -4 route del default vrf v$h2 nexthop via 198.51.100.2
+
+	simple_if_fini $h2 198.51.100.1/24 2001:db8:2::1/64
+}
+
+router_create()
+{
+	ip link set dev $rp1 up
+	ip link set dev $rp2 up
+
+	tc qdisc add dev $rp1 clsact
+
+	__addr_add_del $rp1 add 192.0.2.2/24 2001:db8:1::2/64
+	__addr_add_del $rp2 add 198.51.100.2/24 2001:db8:2::2/64
+}
+
+router_destroy()
+{
+	__addr_add_del $rp2 del 198.51.100.2/24 2001:db8:2::2/64
+	__addr_add_del $rp1 del 192.0.2.2/24 2001:db8:1::2/64
+
+	tc qdisc del dev $rp1 clsact
+
+	ip link set dev $rp2 down
+	ip link set dev $rp1 down
+}
+
+ping_ipv4()
+{
+	ping_test $h1 198.51.100.1 ": h1->h2"
+}
+
+ping_ipv6()
+{
+	ping6_test $h1 2001:db8:2::1 ": h1->h2"
+}
+
+blackhole_ipv4()
+{
+	# Transmit packets from H1 to H2 and make sure they are dropped by the
+	# ASIC and not by the kernel
+	RET=0
+
+	ip -4 route add blackhole 198.51.100.0/30
+	tc filter add dev $rp1 ingress protocol ip pref 1 handle 101 flower \
+		skip_hw dst_ip 198.51.100.1 src_ip 192.0.2.1 ip_proto icmp \
+		action pass
+
+	ip -4 route show 198.51.100.0/30 | grep -q offload
+	check_err $? "route not marked as offloaded when should"
+
+	ping_do $h1 198.51.100.1
+	check_fail $? "ping passed when should not"
+
+	tc_check_packets "dev $rp1 ingress" 101 0
+	check_err $? "packets trapped and not dropped by ASIC"
+
+	log_test "IPv4 blackhole route"
+
+	tc filter del dev $rp1 ingress protocol ip pref 1 handle 101 flower
+	ip -4 route del blackhole 198.51.100.0/30
+}
+
+blackhole_ipv6()
+{
+	RET=0
+
+	ip -6 route add blackhole 2001:db8:2::/120
+	tc filter add dev $rp1 ingress protocol ipv6 pref 1 handle 101 flower \
+		skip_hw dst_ip 2001:db8:2::1 src_ip 2001:db8:1::1 \
+		ip_proto icmpv6 action pass
+
+	ip -6 route show 2001:db8:2::/120 | grep -q offload
+	check_err $? "route not marked as offloaded when should"
+
+	ping6_do $h1 2001:db8:2::1
+	check_fail $? "ping passed when should not"
+
+	tc_check_packets "dev $rp1 ingress" 101 0
+	check_err $? "packets trapped and not dropped by ASIC"
+
+	log_test "IPv6 blackhole route"
+
+	tc filter del dev $rp1 ingress protocol ipv6 pref 1 handle 101 flower
+	ip -6 route del blackhole 2001:db8:2::/120
+}
+
+setup_prepare()
+{
+	h1=${NETIFS[p1]}
+	rp1=${NETIFS[p2]}
+
+	rp2=${NETIFS[p3]}
+	h2=${NETIFS[p4]}
+
+	vrf_prepare
+	forwarding_enable
+
+	h1_create
+	h2_create
+	router_create
+}
+
+cleanup()
+{
+	pre_cleanup
+
+	router_destroy
+	h2_destroy
+	h1_destroy
+
+	forwarding_restore
+	vrf_cleanup
+}
+
+trap cleanup EXIT
+
+setup_prepare
+setup_wait
+
+tests_run
+
+exit $EXIT_STATUS