selftests: mlxsw: Add one-armed router test

Construct a "one-armed router" topology and test that packets are
forwarded by the ASIC and that a copy of the packet is sent to the
kernel, which does not forward the packet again.
Signed-off-by: Ido Schimmel <idosch@mellanox.com>
Signed-off-by: David S. Miller <davem@davemloft.net>

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

+#!/bin/bash
+# SPDX-License-Identifier: GPL-2.0
+#
+# Test a "one-armed router" [1] scenario. Packets forwarded between H1 and H2
+# should be forwarded by the ASIC, but also trapped so that ICMP redirect
+# packets could be potentially generated.
+#
+# 1. https://en.wikipedia.org/wiki/One-armed_router
+#
+# +---------------------------------+
+# | 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 |                                                                      |
+# | +--|--------------------------------------------------------------------+ |
+# | |  + $swp1                   BR0 (802.1d)                               | |
+# | |                                                                       | |
+# | |                            192.0.2.2/24                               | |
+# | |                          2001:db8:1::2/64                             | |
+# | |                           198.51.100.2/24                             | |
+# | |                          2001:db8:2::2/64                             | |
+# | |                                                                       | |
+# | |  + $swp2                                                              | |
+# | +--|--------------------------------------------------------------------+ |
+# |    |                                                                      |
+# +----|----------------------------------------------------------------------+
+#      |
+# +----|----------------------------+
+# |    |  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 fwd_mark_ipv4 fwd_mark_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
+}
+
+switch_create()
+{
+	ip link add name br0 type bridge mcast_snooping 0
+	ip link set dev br0 up
+
+	ip link set dev $swp1 master br0
+	ip link set dev $swp1 up
+	ip link set dev $swp2 master br0
+	ip link set dev $swp2 up
+
+	tc qdisc add dev $swp1 clsact
+	tc qdisc add dev $swp2 clsact
+
+	__addr_add_del br0 add 192.0.2.2/24 2001:db8:1::2/64
+	__addr_add_del br0 add 198.51.100.2/24 2001:db8:2::2/64
+}
+
+switch_destroy()
+{
+	__addr_add_del br0 del 198.51.100.2/24 2001:db8:2::2/64
+	__addr_add_del br0 del 192.0.2.2/24 2001:db8:1::2/64
+
+	tc qdisc del dev $swp2 clsact
+	tc qdisc del dev $swp1 clsact
+
+	ip link set dev $swp2 down
+	ip link set dev $swp2 nomaster
+	ip link set dev $swp1 down
+	ip link set dev $swp1 nomaster
+
+	ip link set dev br0 down
+	ip link del dev br0
+}
+
+ping_ipv4()
+{
+	ping_test $h1 198.51.100.1 ": h1->h2"
+}
+
+ping_ipv6()
+{
+	ping6_test $h1 2001:db8:2::1 ": h1->h2"
+}
+
+fwd_mark_ipv4()
+{
+	# Transmit packets from H1 to H2 and make sure they are trapped at
+	# swp1 due to loopback error, but only forwarded by the ASIC through
+	# swp2
+
+	tc filter add dev $swp1 ingress protocol ip pref 1 handle 101 flower \
+		skip_hw dst_ip 198.51.100.1 ip_proto udp dst_port 52768 \
+		action pass
+
+	tc filter add dev $swp2 egress protocol ip pref 1 handle 101 flower \
+		skip_hw dst_ip 198.51.100.1 ip_proto udp dst_port 52768 \
+		action pass
+
+	tc filter add dev $swp2 egress protocol ip pref 2 handle 102 flower \
+		skip_sw dst_ip 198.51.100.1 ip_proto udp dst_port 52768 \
+		action pass
+
+	ip vrf exec v$h1 $MZ $h1 -c 10 -d 100msec -p 64 -A 192.0.2.1 \
+		-B 198.51.100.1 -t udp dp=52768,sp=42768 -q
+
+	RET=0
+
+	tc_check_packets "dev $swp1 ingress" 101 10
+	check_err $?
+
+	log_test "fwd mark: trapping IPv4 packets due to LBERROR"
+
+	RET=0
+
+	tc_check_packets "dev $swp2 egress" 101 0
+	check_err $?
+
+	log_test "fwd mark: forwarding IPv4 packets in software"
+
+	RET=0
+
+	tc_check_packets "dev $swp2 egress" 102 10
+	check_err $?
+
+	log_test "fwd mark: forwarding IPv4 packets in hardware"
+
+	tc filter del dev $swp2 egress protocol ip pref 2 handle 102 flower
+	tc filter del dev $swp2 egress protocol ip pref 1 handle 101 flower
+	tc filter del dev $swp1 ingress protocol ip pref 1 handle 101 flower
+}
+
+fwd_mark_ipv6()
+{
+	tc filter add dev $swp1 ingress protocol ipv6 pref 1 handle 101 flower \
+		skip_hw dst_ip 2001:db8:2::1 ip_proto udp dst_port 52768 \
+		action pass
+
+	tc filter add dev $swp2 egress protocol ipv6 pref 1 handle 101 flower \
+		skip_hw dst_ip 2001:db8:2::1 ip_proto udp dst_port 52768 \
+		action pass
+
+	tc filter add dev $swp2 egress protocol ipv6 pref 2 handle 102 flower \
+		skip_sw dst_ip 2001:db8:2::1 ip_proto udp dst_port 52768 \
+		action pass
+
+	ip vrf exec v$h1 $MZ $h1 -6 -c 10 -d 100msec -p 64 -A 2001:db8:1::1 \
+		-B 2001:db8:2::1 -t udp dp=52768,sp=42768 -q
+
+	RET=0
+
+	tc_check_packets "dev $swp1 ingress" 101 10
+	check_err $?
+
+	log_test "fwd mark: trapping IPv6 packets due to LBERROR"
+
+	RET=0
+
+	tc_check_packets "dev $swp2 egress" 101 0
+	check_err $?
+
+	log_test "fwd mark: forwarding IPv6 packets in software"
+
+	RET=0
+
+	tc_check_packets "dev $swp2 egress" 102 10
+	check_err $?
+
+	log_test "fwd mark: forwarding IPv6 packets in hardware"
+
+	tc filter del dev $swp2 egress protocol ipv6 pref 2 handle 102 flower
+	tc filter del dev $swp2 egress protocol ipv6 pref 1 handle 101 flower
+	tc filter del dev $swp1 ingress protocol ipv6 pref 1 handle 101 flower
+}
+
+setup_prepare()
+{
+	h1=${NETIFS[p1]}
+	swp1=${NETIFS[p2]}
+
+	swp2=${NETIFS[p3]}
+	h2=${NETIFS[p4]}
+
+	vrf_prepare
+	forwarding_enable
+
+	sysctl_set net.ipv4.conf.all.accept_redirects 0
+	sysctl_set net.ipv6.conf.all.accept_redirects 0
+
+	h1_create
+	h2_create
+	switch_create
+}
+
+cleanup()
+{
+	pre_cleanup
+
+	switch_destroy
+	h2_destroy
+	h1_destroy
+
+	sysctl_restore net.ipv6.conf.all.accept_redirects
+	sysctl_restore net.ipv4.conf.all.accept_redirects
+
+	forwarding_restore
+	vrf_cleanup
+}
+
+trap cleanup EXIT
+
+setup_prepare
+setup_wait
+
+tests_run
+
+exit $EXIT_STATUS