selftests: forwarding: Add test for custom multipath hash with IPv4 GRE

Test that when the hash policy is set to custom, traffic is distributed
only according to the inner fields set in the fib_multipath_hash_fields
sysctl.

Each time set a different field and make sure traffic is only
distributed when the field is changed in the packet stream.

The test only verifies the behavior of IPv4/IPv6 overlays on top of an
IPv4 underlay network. A subsequent patch will do the same with an IPv6
underlay network.

Example output:

# ./gre_custom_multipath_hash.sh
TEST: ping [ OK ]
TEST: ping6 [ OK ]
INFO: Running IPv4 overlay custom multipath hash tests
TEST: Multipath hash field: Inner source IP (balanced) [ OK ]
INFO: Packets sent on path1 / path2: 6601 / 6001
TEST: Multipath hash field: Inner source IP (unbalanced) [ OK ]
INFO: Packets sent on path1 / path2: 0 / 12600
TEST: Multipath hash field: Inner destination IP (balanced) [ OK ]
INFO: Packets sent on path1 / path2: 6802 / 5802
TEST: Multipath hash field: Inner destination IP (unbalanced) [ OK ]
INFO: Packets sent on path1 / path2: 12601 / 1
TEST: Multipath hash field: Inner source port (balanced) [ OK ]
INFO: Packets sent on path1 / path2: 16430 / 16344
TEST: Multipath hash field: Inner source port (unbalanced) [ OK ]
INFO: Packets sent on path1 / path2: 0 / 32772
TEST: Multipath hash field: Inner destination port (balanced) [ OK ]
INFO: Packets sent on path1 / path2: 16430 / 16343
TEST: Multipath hash field: Inner destination port (unbalanced) [ OK ]
INFO: Packets sent on path1 / path2: 0 / 32772
INFO: Running IPv6 overlay custom multipath hash tests
TEST: Multipath hash field: Inner source IP (balanced) [ OK ]
INFO: Packets sent on path1 / path2: 6702 / 5900
TEST: Multipath hash field: Inner source IP (unbalanced) [ OK ]
INFO: Packets sent on path1 / path2: 0 / 12601
TEST: Multipath hash field: Inner destination IP (balanced) [ OK ]
INFO: Packets sent on path1 / path2: 5751 / 6851
TEST: Multipath hash field: Inner destination IP (unbalanced) [ OK ]
INFO: Packets sent on path1 / path2: 12602 / 1
TEST: Multipath hash field: Inner flowlabel (balanced) [ OK ]
INFO: Packets sent on path1 / path2: 8364 / 8065
TEST: Multipath hash field: Inner flowlabel (unbalanced) [ OK ]
INFO: Packets sent on path1 / path2: 12601 / 0
TEST: Multipath hash field: Inner source port (balanced) [ OK ]
INFO: Packets sent on path1 / path2: 16425 / 16349
TEST: Multipath hash field: Inner source port (unbalanced) [ OK ]
INFO: Packets sent on path1 / path2: 1 / 32770
TEST: Multipath hash field: Inner destination port (balanced) [ OK ]
INFO: Packets sent on path1 / path2: 16425 / 16349
TEST: Multipath hash field: Inner destination port (unbalanced) [ OK ]
INFO: Packets sent on path1 / path2: 2 / 32770

Signed-off-by: Ido Schimmel <[e-mail]>
Acked-by: David Ahern <[e-mail]>
Signed-off-by: David S. Miller <[e-mail]>

tools/testing/selftests/net/forwarding/gre_custom_multipath_hash.sh

···
+#!/bin/bash
+# SPDX-License-Identifier: GPL-2.0
+#
+# Test traffic distribution when there are multiple paths between an IPv4 GRE
+# tunnel. The tunnel carries IPv4 and IPv6 traffic between multiple hosts.
+# Multiple routes are in the underlay network. With the default multipath
+# policy, SW2 will only look at the outer IP addresses, hence only a single
+# route would be used.
+#
+# +--------------------------------+
+# | H1                             |
+# |                     $h1 +      |
+# |   198.51.100.{2-253}/24 |      |
+# |   2001:db8:1::{2-fd}/64 |      |
+# +-------------------------|------+
+#                           |
+# +-------------------------|------------------+
+# | SW1                     |                  |
+# |                    $ol1 +                  |
+# |         198.51.100.1/24                    |
+# |        2001:db8:1::1/64                    |
+# |                                            |
+# |   + g1 (gre)                               |
+# |     loc=192.0.2.1                          |
+# |     rem=192.0.2.2 --.                      |
+# |     tos=inherit     |                      |
+# |                     v                      |
+# |                     + $ul1                 |
+# |                     | 192.0.2.17/28        |
+# +---------------------|----------------------+
+#                       |
+# +---------------------|----------------------+
+# | SW2                 |                      |
+# |               $ul21 +                      |
+# |       192.0.2.18/28 |                      |
+# |                     |                      |
+# !   __________________+___                   |
+# |  /                      \                  |
+# |  |                      |                  |
+# |  + $ul22.111 (vlan)     + $ul22.222 (vlan) |
+# |  | 192.0.2.33/28        | 192.0.2.49/28    |
+# |  |                      |                  |
+# +--|----------------------|------------------+
+#    |                      |
+# +--|----------------------|------------------+
+# |  |                      |                  |
+# |  + $ul32.111 (vlan)     + $ul32.222 (vlan) |
+# |  | 192.0.2.34/28        | 192.0.2.50/28    |
+# |  |                      |                  |
+# |  \__________________+___/                  |
+# |                     |                      |
+# |                     |                      |
+# |               $ul31 +                      |
+# |       192.0.2.65/28 |                  SW3 |
+# +---------------------|----------------------+
+#                       |
+# +---------------------|----------------------+
+# |                     + $ul4                 |
+# |                     ^ 192.0.2.66/28        |
+# |                     |                      |
+# |   + g2 (gre)        |                      |
+# |     loc=192.0.2.2   |                      |
+# |     rem=192.0.2.1 --'                      |
+# |     tos=inherit                            |
+# |                                            |
+# |                    $ol4 +                  |
+# |          203.0.113.1/24 |                  |
+# |        2001:db8:2::1/64 |              SW4 |
+# +-------------------------|------------------+
+#                           |
+# +-------------------------|------+
+# |                         |      |
+# |                     $h2 +      |
+# |    203.0.113.{2-253}/24        |
+# |   2001:db8:2::{2-fd}/64     H2 |
+# +--------------------------------+
+
+ALL_TESTS="
+	ping_ipv4
+	ping_ipv6
+	custom_hash
+"
+
+NUM_NETIFS=10
+source lib.sh
+
+h1_create()
+{
+	simple_if_init $h1 198.51.100.2/24 2001:db8:1::2/64
+	ip route add vrf v$h1 default via 198.51.100.1 dev $h1
+	ip -6 route add vrf v$h1 default via 2001:db8:1::1 dev $h1
+}
+
+h1_destroy()
+{
+	ip -6 route del vrf v$h1 default
+	ip route del vrf v$h1 default
+	simple_if_fini $h1 198.51.100.2/24 2001:db8:1::2/64
+}
+
+sw1_create()
+{
+	simple_if_init $ol1 198.51.100.1/24 2001:db8:1::1/64
+	__simple_if_init $ul1 v$ol1 192.0.2.17/28
+
+	tunnel_create g1 gre 192.0.2.1 192.0.2.2 tos inherit dev v$ol1
+	__simple_if_init g1 v$ol1 192.0.2.1/32
+	ip route add vrf v$ol1 192.0.2.2/32 via 192.0.2.18
+
+	ip route add vrf v$ol1 203.0.113.0/24 dev g1
+	ip -6 route add vrf v$ol1 2001:db8:2::/64 dev g1
+}
+
+sw1_destroy()
+{
+	ip -6 route del vrf v$ol1 2001:db8:2::/64
+	ip route del vrf v$ol1 203.0.113.0/24
+
+	ip route del vrf v$ol1 192.0.2.2/32
+	__simple_if_fini g1 192.0.2.1/32
+	tunnel_destroy g1
+
+	__simple_if_fini $ul1 192.0.2.17/28
+	simple_if_fini $ol1 198.51.100.1/24 2001:db8:1::1/64
+}
+
+sw2_create()
+{
+	simple_if_init $ul21 192.0.2.18/28
+	__simple_if_init $ul22 v$ul21
+	vlan_create $ul22 111 v$ul21 192.0.2.33/28
+	vlan_create $ul22 222 v$ul21 192.0.2.49/28
+
+	ip route add vrf v$ul21 192.0.2.1/32 via 192.0.2.17
+	ip route add vrf v$ul21 192.0.2.2/32 \
+	   nexthop via 192.0.2.34 \
+	   nexthop via 192.0.2.50
+}
+
+sw2_destroy()
+{
+	ip route del vrf v$ul21 192.0.2.2/32
+	ip route del vrf v$ul21 192.0.2.1/32
+
+	vlan_destroy $ul22 222
+	vlan_destroy $ul22 111
+	__simple_if_fini $ul22
+	simple_if_fini $ul21 192.0.2.18/28
+}
+
+sw3_create()
+{
+	simple_if_init $ul31 192.0.2.65/28
+	__simple_if_init $ul32 v$ul31
+	vlan_create $ul32 111 v$ul31 192.0.2.34/28
+	vlan_create $ul32 222 v$ul31 192.0.2.50/28
+
+	ip route add vrf v$ul31 192.0.2.2/32 via 192.0.2.66
+	ip route add vrf v$ul31 192.0.2.1/32 \
+	   nexthop via 192.0.2.33 \
+	   nexthop via 192.0.2.49
+
+	tc qdisc add dev $ul32 clsact
+	tc filter add dev $ul32 ingress pref 111 prot 802.1Q \
+	   flower vlan_id 111 action pass
+	tc filter add dev $ul32 ingress pref 222 prot 802.1Q \
+	   flower vlan_id 222 action pass
+}
+
+sw3_destroy()
+{
+	tc qdisc del dev $ul32 clsact
+
+	ip route del vrf v$ul31 192.0.2.1/32
+	ip route del vrf v$ul31 192.0.2.2/32
+
+	vlan_destroy $ul32 222
+	vlan_destroy $ul32 111
+	__simple_if_fini $ul32
+	simple_if_fini $ul31 192.0.2.65/28
+}
+
+sw4_create()
+{
+	simple_if_init $ol4 203.0.113.1/24 2001:db8:2::1/64
+	__simple_if_init $ul4 v$ol4 192.0.2.66/28
+
+	tunnel_create g2 gre 192.0.2.2 192.0.2.1 tos inherit dev v$ol4
+	__simple_if_init g2 v$ol4 192.0.2.2/32
+	ip route add vrf v$ol4 192.0.2.1/32 via 192.0.2.65
+
+	ip route add vrf v$ol4 198.51.100.0/24 dev g2
+	ip -6 route add vrf v$ol4 2001:db8:1::/64 dev g2
+}
+
+sw4_destroy()
+{
+	ip -6 route del vrf v$ol4 2001:db8:1::/64
+	ip route del vrf v$ol4 198.51.100.0/24
+
+	ip route del vrf v$ol4 192.0.2.1/32
+	__simple_if_fini g2 192.0.2.2/32
+	tunnel_destroy g2
+
+	__simple_if_fini $ul4 192.0.2.66/28
+	simple_if_fini $ol4 203.0.113.1/24 2001:db8:2::1/64
+}
+
+h2_create()
+{
+	simple_if_init $h2 203.0.113.2/24 2001:db8:2::2/64
+	ip route add vrf v$h2 default via 203.0.113.1 dev $h2
+	ip -6 route add vrf v$h2 default via 2001:db8:2::1 dev $h2
+}
+
+h2_destroy()
+{
+	ip -6 route del vrf v$h2 default
+	ip route del vrf v$h2 default
+	simple_if_fini $h2 203.0.113.2/24 2001:db8:2::2/64
+}
+
+setup_prepare()
+{
+	h1=${NETIFS[p1]}
+
+	ol1=${NETIFS[p2]}
+	ul1=${NETIFS[p3]}
+
+	ul21=${NETIFS[p4]}
+	ul22=${NETIFS[p5]}
+
+	ul32=${NETIFS[p6]}
+	ul31=${NETIFS[p7]}
+
+	ul4=${NETIFS[p8]}
+	ol4=${NETIFS[p9]}
+
+	h2=${NETIFS[p10]}
+
+	vrf_prepare
+	h1_create
+	sw1_create
+	sw2_create
+	sw3_create
+	sw4_create
+	h2_create
+
+	forwarding_enable
+}
+
+cleanup()
+{
+	pre_cleanup
+
+	forwarding_restore
+
+	h2_destroy
+	sw4_destroy
+	sw3_destroy
+	sw2_destroy
+	sw1_destroy
+	h1_destroy
+	vrf_cleanup
+}
+
+ping_ipv4()
+{
+	ping_test $h1 203.0.113.2
+}
+
+ping_ipv6()
+{
+	ping6_test $h1 2001:db8:2::2
+}
+
+send_src_ipv4()
+{
+	$MZ $h1 -q -p 64 -A "198.51.100.2-198.51.100.253" -B 203.0.113.2 \
+		-d 1msec -c 50 -t udp "sp=20000,dp=30000"
+}
+
+send_dst_ipv4()
+{
+	$MZ $h1 -q -p 64 -A 198.51.100.2 -B "203.0.113.2-203.0.113.253" \
+		-d 1msec -c 50 -t udp "sp=20000,dp=30000"
+}
+
+send_src_udp4()
+{
+	$MZ $h1 -q -p 64 -A 198.51.100.2 -B 203.0.113.2 \
+		-d 1msec -t udp "sp=0-32768,dp=30000"
+}
+
+send_dst_udp4()
+{
+	$MZ $h1 -q -p 64 -A 198.51.100.2 -B 203.0.113.2 \
+		-d 1msec -t udp "sp=20000,dp=0-32768"
+}
+
+send_src_ipv6()
+{
+	$MZ -6 $h1 -q -p 64 -A "2001:db8:1::2-2001:db8:1::fd" -B 2001:db8:2::2 \
+		-d 1msec -c 50 -t udp "sp=20000,dp=30000"
+}
+
+send_dst_ipv6()
+{
+	$MZ -6 $h1 -q -p 64 -A 2001:db8:1::2 -B "2001:db8:2::2-2001:db8:2::fd" \
+		-d 1msec -c 50 -t udp "sp=20000,dp=30000"
+}
+
+send_flowlabel()
+{
+	# Generate 16384 echo requests, each with a random flow label.
+	for _ in $(seq 1 16384); do
+		ip vrf exec v$h1 \
+			$PING6 2001:db8:2::2 -F 0 -c 1 -q >/dev/null 2>&1
+	done
+}
+
+send_src_udp6()
+{
+	$MZ -6 $h1 -q -p 64 -A 2001:db8:1::2 -B 2001:db8:2::2 \
+		-d 1msec -t udp "sp=0-32768,dp=30000"
+}
+
+send_dst_udp6()
+{
+	$MZ -6 $h1 -q -p 64 -A 2001:db8:1::2 -B 2001:db8:2::2 \
+		-d 1msec -t udp "sp=20000,dp=0-32768"
+}
+
+custom_hash_test()
+{
+	local field="$1"; shift
+	local balanced="$1"; shift
+	local send_flows="$@"
+
+	RET=0
+
+	local t0_111=$(tc_rule_stats_get $ul32 111 ingress)
+	local t0_222=$(tc_rule_stats_get $ul32 222 ingress)
+
+	$send_flows
+
+	local t1_111=$(tc_rule_stats_get $ul32 111 ingress)
+	local t1_222=$(tc_rule_stats_get $ul32 222 ingress)
+
+	local d111=$((t1_111 - t0_111))
+	local d222=$((t1_222 - t0_222))
+
+	local diff=$((d222 - d111))
+	local sum=$((d111 + d222))
+
+	local pct=$(echo "$diff / $sum * 100" | bc -l)
+	local is_balanced=$(echo "-20 <= $pct && $pct <= 20" | bc)
+
+	[[ ( $is_balanced -eq 1 && $balanced == "balanced" ) ||
+	   ( $is_balanced -eq 0 && $balanced == "unbalanced" ) ]]
+	check_err $? "Expected traffic to be $balanced, but it is not"
+
+	log_test "Multipath hash field: $field ($balanced)"
+	log_info "Packets sent on path1 / path2: $d111 / $d222"
+}
+
+custom_hash_v4()
+{
+	log_info "Running IPv4 overlay custom multipath hash tests"
+
+	# Prevent the neighbour table from overflowing, as different neighbour
+	# entries will be created on $ol4 when using different destination IPs.
+	sysctl_set net.ipv4.neigh.default.gc_thresh1 1024
+	sysctl_set net.ipv4.neigh.default.gc_thresh2 1024
+	sysctl_set net.ipv4.neigh.default.gc_thresh3 1024
+
+	sysctl_set net.ipv4.fib_multipath_hash_fields 0x0040
+	custom_hash_test "Inner source IP" "balanced" send_src_ipv4
+	custom_hash_test "Inner source IP" "unbalanced" send_dst_ipv4
+
+	sysctl_set net.ipv4.fib_multipath_hash_fields 0x0080
+	custom_hash_test "Inner destination IP" "balanced" send_dst_ipv4
+	custom_hash_test "Inner destination IP" "unbalanced" send_src_ipv4
+
+	sysctl_set net.ipv4.fib_multipath_hash_fields 0x0400
+	custom_hash_test "Inner source port" "balanced" send_src_udp4
+	custom_hash_test "Inner source port" "unbalanced" send_dst_udp4
+
+	sysctl_set net.ipv4.fib_multipath_hash_fields 0x0800
+	custom_hash_test "Inner destination port" "balanced" send_dst_udp4
+	custom_hash_test "Inner destination port" "unbalanced" send_src_udp4
+
+	sysctl_restore net.ipv4.neigh.default.gc_thresh3
+	sysctl_restore net.ipv4.neigh.default.gc_thresh2
+	sysctl_restore net.ipv4.neigh.default.gc_thresh1
+}
+
+custom_hash_v6()
+{
+	log_info "Running IPv6 overlay custom multipath hash tests"
+
+	# Prevent the neighbour table from overflowing, as different neighbour
+	# entries will be created on $ol4 when using different destination IPs.
+	sysctl_set net.ipv6.neigh.default.gc_thresh1 1024
+	sysctl_set net.ipv6.neigh.default.gc_thresh2 1024
+	sysctl_set net.ipv6.neigh.default.gc_thresh3 1024
+
+	sysctl_set net.ipv4.fib_multipath_hash_fields 0x0040
+	custom_hash_test "Inner source IP" "balanced" send_src_ipv6
+	custom_hash_test "Inner source IP" "unbalanced" send_dst_ipv6
+
+	sysctl_set net.ipv4.fib_multipath_hash_fields 0x0080
+	custom_hash_test "Inner destination IP" "balanced" send_dst_ipv6
+	custom_hash_test "Inner destination IP" "unbalanced" send_src_ipv6
+
+	sysctl_set net.ipv4.fib_multipath_hash_fields 0x0200
+	custom_hash_test "Inner flowlabel" "balanced" send_flowlabel
+	custom_hash_test "Inner flowlabel" "unbalanced" send_src_ipv6
+
+	sysctl_set net.ipv4.fib_multipath_hash_fields 0x0400
+	custom_hash_test "Inner source port" "balanced" send_src_udp6
+	custom_hash_test "Inner source port" "unbalanced" send_dst_udp6
+
+	sysctl_set net.ipv4.fib_multipath_hash_fields 0x0800
+	custom_hash_test "Inner destination port" "balanced" send_dst_udp6
+	custom_hash_test "Inner destination port" "unbalanced" send_src_udp6
+
+	sysctl_restore net.ipv6.neigh.default.gc_thresh3
+	sysctl_restore net.ipv6.neigh.default.gc_thresh2
+	sysctl_restore net.ipv6.neigh.default.gc_thresh1
+}
+
+custom_hash()
+{
+	# Test that when the hash policy is set to custom, traffic is
+	# distributed only according to the fields set in the
+	# fib_multipath_hash_fields sysctl.
+	#
+	# Each time set a different field and make sure traffic is only
+	# distributed when the field is changed in the packet stream.
+
+	sysctl_set net.ipv4.fib_multipath_hash_policy 3
+
+	custom_hash_v4
+	custom_hash_v6
+
+	sysctl_restore net.ipv4.fib_multipath_hash_policy
+}
+
+trap cleanup EXIT
+
+setup_prepare
+setup_wait
+tests_run
+
+exit $EXIT_STATUS