[PATCH 3/3] selftests: forwarding: Add test for load-balancing between multiple servers

[Sriram Yagnaraman <sriram.yagnaraman@est.tech>]

Create a topology with 3 hosts, a router each in it's own network
namespace. Test IPv4 and IPv6 multipath routing from h1 to h2/h3 via
router r1 where a multipath route is setup to load-balance between h2
and h3.

See diagram in the test for more information.

Signed-off-by: Sriram Yagnaraman <sriram.yagnaraman@est.tech>
---
 .../testing/selftests/net/forwarding/Makefile |   1 +
 .../net/forwarding/router_multipath_vip.sh    | 403 ++++++++++++++++++
 2 files changed, 404 insertions(+)
 create mode 100755 tools/testing/selftests/net/forwarding/router_multipath_vip.sh

diff --git a/tools/testing/selftests/net/forwarding/Makefile b/tools/testing/selftests/net/forwarding/Makefile
index 770efbe24f0d..bf4e5745fd5c 100644
--- a/tools/testing/selftests/net/forwarding/Makefile
+++ b/tools/testing/selftests/net/forwarding/Makefile
@@ -70,6 +70,7 @@ TEST_PROGS = bridge_igmp.sh \
 	router_mpath_nh.sh \
 	router_multicast.sh \
 	router_multipath.sh \
+	router_multipath_vip.sh \
 	router_nh.sh \
 	router.sh \
 	router_vid_1.sh \
diff --git a/tools/testing/selftests/net/forwarding/router_multipath_vip.sh b/tools/testing/selftests/net/forwarding/router_multipath_vip.sh
new file mode 100755
index 000000000000..15c7598d42df
--- /dev/null
+++ b/tools/testing/selftests/net/forwarding/router_multipath_vip.sh
@@ -0,0 +1,403 @@
+#!/bin/bash
+# SPDX-License-Identifier: GPL-2.0
+
+# +--------------------+                     +----------------------+
+# | H1                 |                     |                   H2 |
+# |                    |                     |                      |
+# |              $h1 + |                     | + $h2                |
+# |     192.0.2.2/24 | |                     | | 198.51.100.2/24    |
+# | 2001:db8:1::2/64 | |                     | | 2001:db8:2::2/64   |
+# |                  | |                     | |                    |
+# +------------------|-+                     +-|--------------------+
+#                    |                         |
+# +------------------|-------------------------|--------------------+
+# | SW               |                         |                    |
+# |                  |                         |                    |
+# |             $rp1 +                         + $rp2               |
+# |     192.0.2.1/24                             198.51.100.1/24    |
+# | 2001:db8:1::1/64     + vip                   2001:db8:2::1/64   |
+# |                        198.18.0.0/24                            |
+# |                        2001:db8:18::/64    + $rp3               |
+# |                                            | 203.0.113.1/24     |
+# |                                            | 2001:db8:3::1/64   |
+# |                                            |                    |
+# |                                            |                    |
+# +--------------------------------------------|--------------------+
+#                                              |
+#                                            +-|--------------------+
+#                                            | |                 H3 |
+#                                            | |                    |
+#                                            | | 203.0.113.2/24     |
+#                                            | | 2001:db8:3::2/64   |
+#                                            | + $h3                |
+#                                            |                      |
+#                                            +----------------------+
+
+ALL_TESTS="ping_ipv4 ping_ipv6 multipath_test"
+NUM_NETIFS=6
+source lib.sh
+
+ns_create()
+{
+	ns=$1
+
+	ip netns add $ns
+	in_ns $ns ip link set dev lo up
+	in_ns $ns sysctl -q -w net.ipv4.ip_forward=1
+	in_ns $ns sysctl -q -w net.ipv6.conf.all.forwarding=1
+}
+
+ns_destroy()
+{
+	ip netns del $1
+}
+
+h1_create()
+{
+	local ns="ns-h1"
+
+	ns_create $ns
+	ip link set dev $h1 netns $ns
+
+	in_ns $ns ip link set dev $h1 up
+
+	in_ns $ns ip address add 192.0.2.2/24 dev $h1
+	in_ns $ns ip address add 2001:db8:1::2/64 dev $h1
+
+	in_ns $ns ip route add default via 192.0.2.1
+	in_ns $ns ip route add default via 2001:db8:1::1
+}
+
+h1_destroy()
+{
+	local ns="ns-h1"
+
+	in_ns $ns ip route del default via 2001:db8:1::1
+	in_ns $ns ip route del default via 192.0.2.1
+
+	in_ns $ns ip address del 2001:db8:1::2/64 dev $h1
+	in_ns $ns ip address del 192.0.2.2/24 dev $h1
+
+	in_ns $ns ip link set dev $h1 down
+	in_ns $ns ip link set dev $h1 netns 1
+	ns_destroy $ns
+}
+
+h2_create()
+{
+	local ns="ns-h2"
+
+	ns_create $ns
+	ip link set dev $h2 netns $ns
+
+	in_ns $ns ip link set dev $h2 up
+
+	in_ns $ns ip address add 198.51.100.2/24 dev $h2
+	in_ns $ns ip address add 2001:db8:2::2/64 dev $h2
+
+	in_ns $ns ip address add 198.18.0.0/24 dev lo
+	in_ns $ns ip address add 2001:db8:18::/64 dev lo
+
+	in_ns $ns ip route add 192.0.2.0/24 via 198.51.100.1
+	in_ns $ns ip route add 2001:db8:1::/64 nexthop via 2001:db8:2::1
+}
+
+h2_destroy()
+{
+	local ns="ns-h2"
+
+	in_ns $ns ip route del 2001:db8:1::/64 nexthop via 2001:db8:2::1
+	in_ns $ns ip route del 192.0.2.0/24 via 198.51.100.1
+
+	in_ns $ns ip address del 2001:db8:18::/64 dev lo
+	in_ns $ns ip address del 198.18.0.0/24 dev lo
+
+	in_ns $ns ip address del 2001:db8:2::2/64 dev $h2
+	in_ns $ns ip address del 198.51.100.2/24 dev $h2
+
+	in_ns $ns ip link set dev $h2 down
+	in_ns $ns ip link set dev $h2 netns 1
+	ns_destroy $ns
+}
+
+h3_create()
+{
+	local ns="ns-h3"
+
+	ns_create $ns
+	ip link set dev $h3 netns $ns
+
+	in_ns $ns ip link set dev $h3 up
+
+	in_ns $ns ip address add 203.0.113.2/24 dev $h3
+	in_ns $ns ip address add 2001:db8:3::2/64 dev $h3
+
+	in_ns $ns ip address add 198.18.0.0/24 dev lo
+	in_ns $ns ip address add 2001:db8:18::/64 dev lo
+
+	in_ns $ns ip route add 192.0.2.0/24 via 203.0.113.1
+	in_ns $ns ip route add 2001:db8:1::/64 nexthop via 2001:db8:3::1
+}
+
+h3_destroy()
+{
+	local ns="ns-h3"
+
+	in_ns $ns ip route del 2001:db8:1::/64 nexthop via 2001:db8:3::1
+	in_ns $ns ip route del 192.0.2.0/24 via 203.0.113.1
+
+	in_ns $ns ip address del 198.18.0.0/24 dev lo
+	in_ns $ns ip address del 2001:db8:18::/64 dev lo
+
+	in_ns $ns ip address del 2001:db8:3::2/64 dev $h3
+	in_ns $ns ip address del 203.0.113.2/24 dev $h3
+
+	in_ns $ns ip link set dev $h3 down
+	in_ns $ns ip link set dev $h3 netns 1
+	ns_destroy $ns
+}
+
+router1_create()
+{
+	local ns="ns-r1"
+
+	ns_create $ns
+	ip link set dev $rp1 netns $ns
+	ip link set dev $rp2 netns $ns
+	ip link set dev $rp3 netns $ns
+
+	in_ns $ns ip link set dev $rp1 up
+	in_ns $ns ip link set dev $rp2 up
+	in_ns $ns ip link set dev $rp3 up
+
+	in_ns $ns ip address add 192.0.2.1/24 dev $rp1
+	in_ns $ns ip address add 2001:db8:1::1/64 dev $rp1
+
+	in_ns $ns ip address add 198.51.100.1/24 dev $rp2
+	in_ns $ns ip address add 2001:db8:2::1/64 dev $rp2
+
+	in_ns $ns ip address add 203.0.113.1/24 dev $rp3
+	in_ns $ns ip address add 2001:db8:3::1/64 dev $rp3
+
+	in_ns $ns ip route add 198.18.0.0/24 \
+		nexthop via 198.51.100.2 \
+		nexthop via 203.0.113.2
+	in_ns $ns ip route add 2001:db8:18::/64 \
+		nexthop via 2001:db8:2::2 \
+		nexthop via 2001:db8:3::2
+}
+
+router1_destroy()
+{
+	local ns="ns-r1"
+
+	in_ns $ns ip route del 2001:db8:18::/64
+	in_ns $ns ip route del 198.18.0.0/24
+
+	in_ns $ns ip address del 2001:db8:3::1/64 dev $rp3
+	in_ns $ns ip address del 203.0.113.1/24 dev $rp3
+
+	in_ns $ns ip address del 2001:db8:2::1/64 dev $rp2
+	in_ns $ns ip address del 198.51.100.1/24 dev $rp2
+
+	in_ns $ns ip address del 2001:db8:1::1/64 dev $rp1
+	in_ns $ns ip address del 192.0.2.1/24 dev $rp1
+
+	in_ns $ns ip link set dev $rp3 down
+	in_ns $ns ip link set dev $rp2 down
+	in_ns $ns ip link set dev $rp1 down
+
+	in_ns $ns ip link set dev $rp3 netns 1
+	in_ns $ns ip link set dev $rp2 netns 1
+	in_ns $ns ip link set dev $rp1 netns 1
+	ns_destroy $ns
+}
+
+multipath4_test()
+{
+	local desc="$1"
+	local weight_rp2=$2
+	local weight_rp3=$3
+	local t0_rp2 t0_rp3 t1_rp2 t1_rp3
+	local packets_rp2 packets_rp3
+
+	# Transmit multiple flows from h1 to h2 and make sure they are
+	# distributed between both multipath links (rp2 and rp3)
+	# according to the configured weights.
+	in_ns ns-r1 sysctl_set net.ipv4.fib_multipath_hash_policy 1
+	in_ns ns-r1 ip route replace 198.18.0.0/24 \
+		nexthop via 198.51.100.2 weight $weight_rp2 \
+		nexthop via 203.0.113.2 weight $weight_rp3
+
+	t0_rp2=$(in_ns ns-r1 link_stats_tx_packets_get $rp2)
+	t0_rp3=$(in_ns ns-r1 link_stats_tx_packets_get $rp3)
+
+	in_ns ns-h1 $MZ $h1 -q -p 64 -A 192.0.2.2 -B 198.18.0.0 \
+		-d 1msec -t udp "sp=1024,dp=0-32768"
+
+	t1_rp2=$(in_ns ns-r1 link_stats_tx_packets_get $rp2)
+	t1_rp3=$(in_ns ns-r1 link_stats_tx_packets_get $rp3)
+
+	let "packets_rp2 = $t1_rp2 - $t0_rp2"
+	let "packets_rp3 = $t1_rp3 - $t0_rp3"
+	in_ns ns-r1 multipath_eval "$desc" $weight_rp2 $weight_rp3 $packets_rp2 $packets_rp3
+
+	in_ns ns-r1 ip route replace 198.18.0.0/24 \
+		nexthop via 198.51.100.2 \
+		nexthop via 203.0.113.2
+
+	in_ns ns-r1 sysctl_restore net.ipv4.fib_multipath_hash_policy
+}
+
+multipath6_l4_test()
+{
+	local desc="$1"
+	local weight_rp2=$2
+	local weight_rp3=$3
+	local t0_rp2 t0_rp3 t1_rp2 t1_rp3
+	local packets_rp2 packets_rp3
+
+	# Transmit multiple flows from h1 to h2 and make sure they are
+	# distributed between both multipath links (rp2 and rp3)
+	# according to the configured weights.
+	in_ns ns-r1 sysctl_set net.ipv6.fib_multipath_hash_policy 1
+	in_ns ns-r1 ip route replace 2001:db8:18::/64 \
+		nexthop via 2001:db8:2::2 weight $weight_rp2 \
+		nexthop via 2001:db8:3::2 weight $weight_rp3
+
+	t0_rp2=$(in_ns ns-r1 link_stats_tx_packets_get $rp2)
+	t0_rp3=$(in_ns ns-r1 link_stats_tx_packets_get $rp3)
+
+	in_ns ns-h1 $MZ $h1 -6 -q -p 64 -A 2001:db8:1::2 -B 2001:db8:18::0 \
+		-d 1msec -t udp "sp=1024,dp=0-32768"
+
+	t1_rp2=$(in_ns ns-r1 link_stats_tx_packets_get $rp2)
+	t1_rp3=$(in_ns ns-r1 link_stats_tx_packets_get $rp3)
+
+	let "packets_rp2 = $t1_rp2 - $t0_rp2"
+	let "packets_rp3 = $t1_rp3 - $t0_rp3"
+	in_ns ns-r1 multipath_eval "$desc" $weight_rp2 $weight_rp3 $packets_rp2 $packets_rp3
+
+	in_ns ns-r1 ip route replace 2001:db8:18::/64 \
+		nexthop via 2001:db8:2::2 \
+		nexthop via 2001:db8:3::2
+
+	in_ns ns-r1 sysctl_restore net.ipv6.fib_multipath_hash_policy
+}
+
+multipath_test()
+{
+	log_info "Running IPv4 multipath tests"
+	multipath4_test "ECMP" 1 1
+	multipath4_test "Weighted MP 2:1" 2 1
+	multipath4_test "Weighted MP 11:45" 11 45
+
+	log_info "Running IPv6 L4 hash multipath tests"
+	multipath6_l4_test "ECMP" 1 1
+	multipath6_l4_test "Weighted MP 2:1" 2 1
+	multipath6_l4_test "Weighted MP 11:45" 11 45
+}
+
+setup_prepare()
+{
+	h1=${NETIFS[p1]}
+	rp1=${NETIFS[p2]}
+
+	rp2=${NETIFS[p3]}
+	h2=${NETIFS[p4]}
+
+	rp3=${NETIFS[p5]}
+	h3=${NETIFS[p6]}
+
+	h1_create
+	h2_create
+	h3_create
+
+	router1_create
+
+	forwarding_enable
+}
+
+setup_wait()
+{
+	h1=${NETIFS[p1]}
+	rp1=${NETIFS[p2]}
+
+	rp2=${NETIFS[p3]}
+	h2=${NETIFS[p4]}
+
+	rp3=${NETIFS[p5]}
+	h3=${NETIFS[p6]}
+
+	in_ns ns-h1 setup_wait_dev $h1
+	in_ns ns-h2 setup_wait_dev $h2
+	in_ns ns-h3 setup_wait_dev $h3
+	in_ns ns-r1 setup_wait_dev $rp1
+	in_ns ns-r1 setup_wait_dev $rp2
+	in_ns ns-r1 setup_wait_dev $rp3
+
+	# Make sure links are ready.
+	sleep $WAIT_TIME
+}
+
+cleanup()
+{
+	pre_cleanup
+
+	forwarding_restore
+
+	router1_destroy
+
+	h3_destroy
+	h2_destroy
+	h1_destroy
+}
+
+ping_test()
+{
+	RET=0
+
+	local ns=$1
+	local dip=$2
+	local args=$3
+
+	in_ns $ns $PING $args $dip -c $PING_COUNT -i 0.1 \
+		-w $PING_TIMEOUT &> /dev/null
+	check_err $?
+	log_test "ping$args"
+}
+
+ping6_test()
+{
+	RET=0
+
+	local ns=$1
+	local dip=$2
+	local args=$3
+
+	in_ns $ns $PING6 $args $dip -c $PING_COUNT -i 0.1 \
+		-w $PING_TIMEOUT &> /dev/null
+	check_err $?
+	log_test "ping6$args"
+}
+
+ping_ipv4()
+{
+	ping_test ns-h1 198.51.100.2
+	ping_test ns-h1 203.0.113.2
+}
+
+ping_ipv6()
+{
+	ping6_test ns-h1 2001:db8:2::2
+	ping6_test ns-h1 2001:db8:3::2
+}
+
+trap cleanup EXIT
+
+setup_prepare
+setup_wait
+
+tests_run
+
+exit $EXIT_STATUS
-- 
2.34.1