selftests: forwarding: Test multipath hashing on inner IP pkts for GRE tunnel

Add selftest scripts for multipath hashing on inner IP pkts when there
is a single GRE tunnel but there are multiple underlay routes to reach
the other end of the tunnel.

Four cases are covered in these scripts:
    - IPv4 inner, IPv4 outer
    - IPv6 inner, IPv4 outer
    - IPv4 inner, IPv6 outer
    - IPv6 inner, IPv6 outer

Reviewed-by: Ido Schimmel <idosch@mellanox.com>
Signed-off-by: Stephen Suryaputra <ssuryaextr@gmail.com>
Signed-off-by: David S. Miller <davem@davemloft.net>

4 files changed, 1220 insertions, 0 deletions

diff --git a/tools/testing/selftests/net/forwarding/gre_inner_v4_multipath.sh b/tools/testing/selftests/net/forwarding/gre_inner_v4_multipath.sh
new file mode 100755
index 000000000000..e4009f658003
--- /dev/null
+++ b/tools/testing/selftests/net/forwarding/gre_inner_v4_multipath.sh
@@ -0,0 +1,305 @@
+#!/bin/bash
+# SPDX-License-Identifier: GPL-2.0
+
+# Test traffic distribution when there are multiple routes between an IPv4
+# GRE tunnel. The tunnel carries IPv4 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 +     |
+# | 192.0.3.{2-62}/24 |     |
+# +-------------------|-----+
+#                     |
+# +-------------------|------------------------+
+# | SW1               |                        |
+# |              $ol1 +                        |
+# |      192.0.3.1/24                          |
+# |                                            |
+# |  + g1 (gre)                                |
+# |    loc=192.0.2.65                          |
+# |    rem=192.0.2.66 --.                      |
+# |    tos=inherit      |                      |
+# |                     v                      |
+# |                     + $ul1                 |
+# |                     | 192.0.2.129/28       |
+# +---------------------|----------------------+
+#                       |
+# +---------------------|----------------------+
+# | SW2                 |                      |
+# |               $ul21 +                      |
+# |      192.0.2.130/28                        |
+# |                   |                        |
+# !   ________________|_____                   |
+# |  /                      \                  |
+# |  |                      |                  |
+# |  + $ul22.111 (vlan)     + $ul22.222 (vlan) |
+# |  | 192.0.2.145/28       | 192.0.2.161/28   |
+# |  |                      |                  |
+# +--|----------------------|------------------+
+#    |                      |
+# +--|----------------------|------------------+
+# |  |                      |                  |
+# |  + $ul32.111 (vlan)     + $ul32.222 (vlan) |
+# |  | 192.0.2.146/28       | 192.0.2.162/28   |
+# |  |                      |                  |
+# |  \______________________/                  |
+# |                   |                        |
+# |                   |                        |
+# |               $ul31 +                      |
+# |      192.0.2.177/28 |                  SW3 |
+# +---------------------|----------------------+
+#                       |
+# +---------------------|----------------------+
+# |                     + $ul4                 |
+# |                     ^ 192.0.2.178/28       |
+# |                     |                      |
+# |  + g2 (gre)         |                      |
+# |    loc=192.0.2.66   |                      |
+# |    rem=192.0.2.65 --'                      |
+# |    tos=inherit                             |
+# |                                            |
+# |               $ol4 +                       |
+# |       192.0.4.1/24 |                   SW4 |
+# +--------------------|-----------------------+
+#                      |
+# +--------------------|---------+
+# |                    |         |
+# |                $h2 +         |
+# |  192.0.4.{2-62}/24        H2 |
+# +------------------------------+
+
+ALL_TESTS="
+	ping_ipv4
+	multipath_ipv4
+"
+
+NUM_NETIFS=10
+source lib.sh
+
+h1_create()
+{
+	simple_if_init $h1 192.0.3.2/24
+	ip route add vrf v$h1 192.0.4.0/24 via 192.0.3.1
+}
+
+h1_destroy()
+{
+	ip route del vrf v$h1 192.0.4.0/24 via 192.0.3.1
+	simple_if_fini $h1 192.0.3.2/24
+}
+
+sw1_create()
+{
+	simple_if_init $ol1 192.0.3.1/24
+	__simple_if_init $ul1 v$ol1 192.0.2.129/28
+
+	tunnel_create g1 gre 192.0.2.65 192.0.2.66 tos inherit dev v$ol1
+	__simple_if_init g1 v$ol1 192.0.2.65/32
+	ip route add vrf v$ol1 192.0.2.66/32 via 192.0.2.130
+
+	ip route add vrf v$ol1 192.0.4.0/24 nexthop dev g1
+}
+
+sw1_destroy()
+{
+	ip route del vrf v$ol1 192.0.4.0/24
+
+	ip route del vrf v$ol1 192.0.2.66/32
+	__simple_if_fini g1 192.0.2.65/32
+	tunnel_destroy g1
+
+	__simple_if_fini $ul1 192.0.2.129/28
+	simple_if_fini $ol1 192.0.3.1/24
+}
+
+sw2_create()
+{
+	simple_if_init $ul21 192.0.2.130/28
+	__simple_if_init $ul22 v$ul21
+	vlan_create $ul22 111 v$ul21 192.0.2.145/28
+	vlan_create $ul22 222 v$ul21 192.0.2.161/28
+
+	ip route add vrf v$ul21 192.0.2.65/32 via 192.0.2.129
+	ip route add vrf v$ul21 192.0.2.66/32 \
+	   nexthop via 192.0.2.146 \
+	   nexthop via 192.0.2.162
+}
+
+sw2_destroy()
+{
+	ip route del vrf v$ul21 192.0.2.66/32
+	ip route del vrf v$ul21 192.0.2.65/32
+
+	vlan_destroy $ul22 222
+	vlan_destroy $ul22 111
+	__simple_if_fini $ul22
+	simple_if_fini $ul21 192.0.2.130/28
+}
+
+sw3_create()
+{
+	simple_if_init $ul31 192.0.2.177/28
+	__simple_if_init $ul32 v$ul31
+	vlan_create $ul32 111 v$ul31 192.0.2.146/28
+	vlan_create $ul32 222 v$ul31 192.0.2.162/28
+
+	ip route add vrf v$ul31 192.0.2.66/32 via 192.0.2.178
+	ip route add vrf v$ul31 192.0.2.65/32 \
+	   nexthop via 192.0.2.145 \
+	   nexthop via 192.0.2.161
+
+	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 192.0.2.65/32
+	ip route del vrf v$ul31 192.0.2.66/32
+
+	vlan_destroy $ul32 222
+	vlan_destroy $ul32 111
+	__simple_if_fini $ul32
+	simple_if_fini $ul31 192.0.2.177/28
+}
+
+sw4_create()
+{
+	simple_if_init $ol4 192.0.4.1/24
+	__simple_if_init $ul4 v$ol4 192.0.2.178/28
+
+	tunnel_create g2 gre 192.0.2.66 192.0.2.65 tos inherit dev v$ol4
+	__simple_if_init g2 v$ol4 192.0.2.66/32
+	ip route add vrf v$ol4 192.0.2.65/32 via 192.0.2.177
+
+	ip route add vrf v$ol4 192.0.3.0/24 nexthop dev g2
+}
+
+sw4_destroy()
+{
+	ip route del vrf v$ol4 192.0.3.0/24
+
+	ip route del vrf v$ol4 192.0.2.65/32
+	__simple_if_fini g2 192.0.2.66/32
+	tunnel_destroy g2
+
+	__simple_if_fini $ul4 192.0.2.178/28
+	simple_if_fini $ol4 192.0.4.1/24
+}
+
+h2_create()
+{
+	simple_if_init $h2 192.0.4.2/24
+	ip route add vrf v$h2 192.0.3.0/24 via 192.0.4.1
+}
+
+h2_destroy()
+{
+	ip route del vrf v$h2 192.0.3.0/24 via 192.0.4.1
+	simple_if_fini $h2 192.0.4.2/24
+}
+
+setup_prepare()
+{
+	h1=${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
+}
+
+multipath4_test()
+{
+	local what=$1; shift
+	local weight1=$1; shift
+	local weight2=$1; shift
+
+	sysctl_set net.ipv4.fib_multipath_hash_policy 2
+	ip route replace vrf v$ul21 192.0.2.66/32 \
+	   nexthop via 192.0.2.146 weight $weight1 \
+	   nexthop via 192.0.2.162 weight $weight2
+
+	local t0_111=$(tc_rule_stats_get $ul32 111 ingress)
+	local t0_222=$(tc_rule_stats_get $ul32 222 ingress)
+
+	ip vrf exec v$h1 \
+	   $MZ $h1 -q -p 64 -A "192.0.3.2-192.0.3.62" -B "192.0.4.2-192.0.4.62" \
+	       -d 1msec -c 50 -t udp "sp=1024,dp=1024"
+	sleep 1
+
+	local t1_111=$(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=$((t1_222 - t0_222))
+	multipath_eval "$what" $weight1 $weight2 $d111 $d222
+
+	ip route replace vrf v$ul21 192.0.2.66/32 \
+	   nexthop via 192.0.2.146 \
+	   nexthop via 192.0.2.162
+	sysctl_restore net.ipv4.fib_multipath_hash_policy
+}
+
+ping_ipv4()
+{
+	ping_test $h1 192.0.4.2
+}
+
+multipath_ipv4()
+{
+	log_info "Running IPv4 over GRE over IPv4 multipath tests"
+	multipath4_test "ECMP" 1 1
+	multipath4_test "Weighted MP 2:1" 2 1
+	multipath4_test "Weighted MP 11:45" 11 45
+}
+
+trap cleanup EXIT
+
+setup_prepare
+setup_wait
+tests_run
+
+exit $EXIT_STATUS
diff --git a/tools/testing/selftests/net/forwarding/gre_inner_v6_multipath.sh b/tools/testing/selftests/net/forwarding/gre_inner_v6_multipath.sh
new file mode 100755
index 000000000000..e449475c4d3e
--- /dev/null
+++ b/tools/testing/selftests/net/forwarding/gre_inner_v6_multipath.sh
@@ -0,0 +1,306 @@
+#!/bin/bash
+# SPDX-License-Identifier: GPL-2.0
+
+# Test traffic distribution when there are multiple routes between an IPv4
+# GRE tunnel. The tunnel carries 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 +     |
+# |  2001:db8:1::2/64 |     |
+# +-------------------|-----+
+#                     |
+# +-------------------|------------------------+
+# | SW1               |                        |
+# |              $ol1 +                        |
+# |  2001:db8:1::1/64                          |
+# |                                            |
+# |  + g1 (gre)                                |
+# |    loc=192.0.2.65                          |
+# |    rem=192.0.2.66 --.                      |
+# |    tos=inherit      |                      |
+# |                     v                      |
+# |                     + $ul1                 |
+# |                     | 192.0.2.129/28       |
+# +---------------------|----------------------+
+#                       |
+# +---------------------|----------------------+
+# | SW2                 |                      |
+# |               $ul21 +                      |
+# |      192.0.2.130/28                        |
+# |                   |                        |
+# !   ________________|_____                   |
+# |  /                      \                  |
+# |  |                      |                  |
+# |  + $ul22.111 (vlan)     + $ul22.222 (vlan) |
+# |  | 192.0.2.145/28       | 192.0.2.161/28   |
+# |  |                      |                  |
+# +--|----------------------|------------------+
+#    |                      |
+# +--|----------------------|------------------+
+# |  |                      |                  |
+# |  + $ul32.111 (vlan)     + $ul32.222 (vlan) |
+# |  | 192.0.2.146/28       | 192.0.2.162/28   |
+# |  |                      |                  |
+# |  \______________________/                  |
+# |                   |                        |
+# |                   |                        |
+# |               $ul31 +                      |
+# |      192.0.2.177/28 |                  SW3 |
+# +---------------------|----------------------+
+#                       |
+# +---------------------|----------------------+
+# |                     + $ul4                 |
+# |                     ^ 192.0.2.178/28       |
+# |                     |                      |
+# |  + g2 (gre)         |                      |
+# |    loc=192.0.2.66   |                      |
+# |    rem=192.0.2.65 --'                      |
+# |    tos=inherit                             |
+# |                                            |
+# |               $ol4 +                       |
+# |   2001:db8:2::1/64 |                   SW4 |
+# +--------------------|-----------------------+
+#                      |
+# +--------------------|---------+
+# |                    |         |
+# |                $h2 +         |
+# |   2001:db8:2::2/64        H2 |
+# +------------------------------+
+
+ALL_TESTS="
+	ping_ipv6
+	multipath_ipv6
+"
+
+NUM_NETIFS=10
+source lib.sh
+
+h1_create()
+{
+	simple_if_init $h1 2001:db8:1::2/64
+	ip -6 route add vrf v$h1 2001:db8:2::/64 via 2001:db8:1::1
+}
+
+h1_destroy()
+{
+	ip -6 route del vrf v$h1 2001:db8:2::/64 via 2001:db8:1::1
+	simple_if_fini $h1 2001:db8:1::2/64
+}
+
+sw1_create()
+{
+	simple_if_init $ol1 2001:db8:1::1/64
+	__simple_if_init $ul1 v$ol1 192.0.2.129/28
+
+	tunnel_create g1 gre 192.0.2.65 192.0.2.66 tos inherit dev v$ol1
+	__simple_if_init g1 v$ol1 192.0.2.65/32
+	ip route add vrf v$ol1 192.0.2.66/32 via 192.0.2.130
+
+	ip -6 route add vrf v$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 192.0.2.66/32
+	__simple_if_fini g1 192.0.2.65/32
+	tunnel_destroy g1
+
+	__simple_if_fini $ul1 192.0.2.129/28
+	simple_if_fini $ol1 2001:db8:1::1/64
+}
+
+sw2_create()
+{
+	simple_if_init $ul21 192.0.2.130/28
+	__simple_if_init $ul22 v$ul21
+	vlan_create $ul22 111 v$ul21 192.0.2.145/28
+	vlan_create $ul22 222 v$ul21 192.0.2.161/28
+
+	ip route add vrf v$ul21 192.0.2.65/32 via 192.0.2.129
+	ip route add vrf v$ul21 192.0.2.66/32 \
+	   nexthop via 192.0.2.146 \
+	   nexthop via 192.0.2.162
+}
+
+sw2_destroy()
+{
+	ip route del vrf v$ul21 192.0.2.66/32
+	ip route del vrf v$ul21 192.0.2.65/32
+
+	vlan_destroy $ul22 222
+	vlan_destroy $ul22 111
+	__simple_if_fini $ul22
+	simple_if_fini $ul21 192.0.2.130/28
+}
+
+sw3_create()
+{
+	simple_if_init $ul31 192.0.2.177/28
+	__simple_if_init $ul32 v$ul31
+	vlan_create $ul32 111 v$ul31 192.0.2.146/28
+	vlan_create $ul32 222 v$ul31 192.0.2.162/28
+
+	ip route add vrf v$ul31 192.0.2.66/32 via 192.0.2.178
+	ip route add vrf v$ul31 192.0.2.65/32 \
+	   nexthop via 192.0.2.145 \
+	   nexthop via 192.0.2.161
+
+	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 192.0.2.65/32
+	ip route del vrf v$ul31 192.0.2.66/32
+
+	vlan_destroy $ul32 222
+	vlan_destroy $ul32 111
+	__simple_if_fini $ul32
+	simple_if_fini $ul31 192.0.2.177/28
+}
+
+sw4_create()
+{
+	simple_if_init $ol4 2001:db8:2::1/64
+	__simple_if_init $ul4 v$ol4 192.0.2.178/28
+
+	tunnel_create g2 gre 192.0.2.66 192.0.2.65 tos inherit dev v$ol4
+	__simple_if_init g2 v$ol4 192.0.2.66/32
+	ip route add vrf v$ol4 192.0.2.65/32 via 192.0.2.177
+
+	ip -6 route add vrf v$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 192.0.2.65/32
+	__simple_if_fini g2 192.0.2.66/32
+	tunnel_destroy g2
+
+	__simple_if_fini $ul4 192.0.2.178/28
+	simple_if_fini $ol4 2001:db8:2::1/64
+}
+
+h2_create()
+{
+	simple_if_init $h2 2001:db8:2::2/64
+	ip -6 route add vrf v$h2 2001:db8:1::/64 via 2001:db8:2::1
+}
+
+h2_destroy()
+{
+	ip -6 route del vrf v$h2 2001:db8:1::/64 via 2001:db8:2::1
+	simple_if_fini $h2 2001:db8:2::2/64
+}
+
+setup_prepare()
+{
+	h1=${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
+}
+
+multipath6_test()
+{
+	local what=$1; shift
+	local weight1=$1; shift
+	local weight2=$1; shift
+
+	sysctl_set net.ipv4.fib_multipath_hash_policy 2
+	ip route replace vrf v$ul21 192.0.2.66/32 \
+	   nexthop via 192.0.2.146 weight $weight1 \
+	   nexthop via 192.0.2.162 weight $weight2
+
+	local t0_111=$(tc_rule_stats_get $ul32 111 ingress)
+	local t0_222=$(tc_rule_stats_get $ul32 222 ingress)
+
+	ip vrf exec v$h1 \
+	   $MZ $h1 -6 -q -p 64 -A "2001:db8:1::2-2001:db8:1::1e" \
+	       -B "2001:db8:2::2-2001:db8:2::1e" \
+	       -d 1msec -c 50 -t udp "sp=1024,dp=1024"
+	sleep 1
+
+	local t1_111=$(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=$((t1_222 - t0_222))
+	multipath_eval "$what" $weight1 $weight2 $d111 $d222
+
+	ip route replace vrf v$ul21 192.0.2.66/32 \
+	   nexthop via 192.0.2.146 \
+	   nexthop via 192.0.2.162
+	sysctl_restore net.ipv4.fib_multipath_hash_policy
+}
+
+ping_ipv6()
+{
+	ping_test $h1 2001:db8:2::2
+}
+
+multipath_ipv6()
+{
+	log_info "Running IPv6 over GRE over IPv4 multipath tests"
+	multipath6_test "ECMP" 1 1
+	multipath6_test "Weighted MP 2:1" 2 1
+	multipath6_test "Weighted MP 11:45" 11 45
+}
+
+trap cleanup EXIT
+
+setup_prepare
+setup_wait
+tests_run
+
+exit $EXIT_STATUS
diff --git a/tools/testing/selftests/net/forwarding/ip6gre_inner_v4_multipath.sh b/tools/testing/selftests/net/forwarding/ip6gre_inner_v4_multipath.sh
new file mode 100755
index 000000000000..a257979d3fc5
--- /dev/null
+++ b/tools/testing/selftests/net/forwarding/ip6gre_inner_v4_multipath.sh
@@ -0,0 +1,304 @@
+#!/bin/bash
+# SPDX-License-Identifier: GPL-2.0
+
+# Test traffic distribution when there are multiple routes between an IPv6
+# GRE tunnel. The tunnel carries IPv4 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 +     |
+# | 192.0.3.{2-62}/24 |     |
+# +-------------------|-----+
+#                     |
+# +-------------------|-------------------------+
+# | SW1               |                         |
+# |              $ol1 +                         |
+# |      192.0.3.1/24                           |
+# |                                             |
+# |  + g1 (gre)                                 |
+# |    loc=2001:db8:40::1                       |
+# |    rem=2001:db8:40::2 --.                   |
+# |    tos=inherit          |                   |
+# |                         v                   |
+# |                         + $ul1              |
+# |                         | 2001:db8:80::1/64 |
+# +-------------------------|-------------------+
+#                           |
+# +-------------------------|-------------------+
+# | SW2                     |                   |
+# |                   $ul21 +                   |
+# |       2001:db8:80::2/64                     |
+# |                   |                         |
+# !   ________________|_____                    |
+# |  /                      \                   |
+# |  |                      |                   |
+# |  + $ul22.111 (vlan)     + $ul22.222 (vlan)  |
+# |  | 2001:db8:81::1/64    | 2001:db8:82::1/64 |
+# |  |                      |                   |
+# +--|----------------------|-------------------+
+#    |                      |
+# +--|----------------------|-------------------+
+# |  |                      |                   |
+# |  + $ul32.111 (vlan)     + $ul32.222 (vlan)  |
+# |  | 2001:db8:81::2/64    | 2001:db8:82::2/64 |
+# |  |                      |                   |
+# |  \______________________/                   |
+# |                   |                         |
+# |                   |                         |
+# |                   $ul31 +                   |
+# |       2001:db8:83::2/64 |               SW3 |
+# +-------------------------|-------------------+
+#                           |
+# +-------------------------|-------------------+
+# |                         + $ul4              |
+# |                         ^ 2001:db8:83::1/64 |
+# |  + g2 (gre)             |                   |
+# |    loc=2001:db8:40::2   |                   |
+# |    rem=2001:db8:40::1 --'                   |
+# |    tos=inherit                              |
+# |                                             |
+# |               $ol4 +                        |
+# |       192.0.4.1/24 |                    SW4 |
+# +--------------------|------------------------+
+#                      |
+# +--------------------|---------+
+# |                    |         |
+# |                $h2 +         |
+# |  192.0.4.{2-62}/24        H2 |
+# +------------------------------+
+
+ALL_TESTS="
+	ping_ipv4
+	multipath_ipv4
+"
+
+NUM_NETIFS=10
+source lib.sh
+
+h1_create()
+{
+	simple_if_init $h1 192.0.3.2/24
+	ip route add vrf v$h1 192.0.4.0/24 via 192.0.3.1
+}
+
+h1_destroy()
+{
+	ip route del vrf v$h1 192.0.4.0/24 via 192.0.3.1
+	simple_if_fini $h1 192.0.3.2/24
+}
+
+sw1_create()
+{
+	simple_if_init $ol1 192.0.3.1/24
+	__simple_if_init $ul1 v$ol1 2001:db8:80::1/64
+
+	tunnel_create g1 ip6gre 2001:db8:40::1 2001:db8:40::2 tos inherit dev v$ol1
+	__simple_if_init g1 v$ol1 2001:db8:40::1/128
+	ip -6 route add vrf v$ol1 2001:db8:40::2/128 via 2001:db8:80::2
+
+	ip route add vrf v$ol1 192.0.4.0/24 nexthop dev g1
+}
+
+sw1_destroy()
+{
+	ip route del vrf v$ol1 192.0.4.0/24
+
+	ip -6 route del vrf v$ol1 2001:db8:40::2/128
+	__simple_if_fini g1 2001:db8:40::1/128
+	tunnel_destroy g1
+
+	__simple_if_fini $ul1 2001:db8:80::1/64
+	simple_if_fini $ol1 192.0.3.1/24
+}
+
+sw2_create()
+{
+	simple_if_init $ul21 2001:db8:80::2/64
+	__simple_if_init $ul22 v$ul21
+	vlan_create $ul22 111 v$ul21 2001:db8:81::1/64
+	vlan_create $ul22 222 v$ul21 2001:db8:82::1/64
+
+	ip -6 route add vrf v$ul21 2001:db8:40::1/128 via 2001:db8:80::1
+	ip -6 route add vrf v$ul21 2001:db8:40::2/128 \
+	   nexthop via 2001:db8:81::2 \
+	   nexthop via 2001:db8:82::2
+}
+
+sw2_destroy()
+{
+	ip -6 route del vrf v$ul21 2001:db8:40::2/128
+	ip -6 route del vrf v$ul21 2001:db8:40::1/128
+
+	vlan_destroy $ul22 222
+	vlan_destroy $ul22 111
+	__simple_if_fini $ul22
+	simple_if_fini $ul21 2001:db8:80::2/64
+}
+
+sw3_create()
+{
+	simple_if_init $ul31 2001:db8:83::2/64
+	__simple_if_init $ul32 v$ul31
+	vlan_create $ul32 111 v$ul31 2001:db8:81::2/64
+	vlan_create $ul32 222 v$ul31 2001:db8:82::2/64
+
+	ip -6 route add vrf v$ul31 2001:db8:40::2/128 via 2001:db8:83::1
+	ip -6 route add vrf v$ul31 2001:db8:40::1/128 \
+	   nexthop via 2001:db8:81::1 \
+	   nexthop via 2001:db8:82::1
+
+	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 $ul32 clsact
+
+	ip -6 route del vrf v$ul31 2001:db8:40::1/128
+	ip -6 route del vrf v$ul31 2001:db8:40::2/128
+
+	vlan_destroy $ul32 222
+	vlan_destroy $ul32 111
+	__simple_if_fini $ul32
+	simple_if_fini $ul31 2001:Db8:83::2/64
+}
+
+sw4_create()
+{
+	simple_if_init $ol4 192.0.4.1/24
+	__simple_if_init $ul4 v$ol4 2001:db8:83::1/64
+
+	tunnel_create g2 ip6gre 2001:db8:40::2 2001:db8:40::1 tos inherit dev v$ol4
+	__simple_if_init g2 v$ol4 2001:db8:40::2/128
+	ip -6 route add vrf v$ol4 2001:db8:40::1/128 via 2001:db8:83::2
+
+	ip route add vrf v$ol4 192.0.3.0/24 nexthop dev g2
+}
+
+sw4_destroy()
+{
+	ip route del vrf v$ol4 192.0.3.0/24
+
+	ip -6 route del vrf v$ol4 2001:db8:40::1/128
+	__simple_if_fini g2 2001:db8:40::2/128
+	tunnel_destroy g2
+
+	__simple_if_fini $ul4 2001:db8:83::1/64
+	simple_if_fini $ol4 192.0.4.1/24
+}
+
+h2_create()
+{
+	simple_if_init $h2 192.0.4.2/24
+	ip route add vrf v$h2 192.0.3.0/24 via 192.0.4.1
+}
+
+h2_destroy()
+{
+	ip route del vrf v$h2 192.0.3.0/24 via 192.0.4.1
+	simple_if_fini $h2 192.0.4.2/24
+}
+
+setup_prepare()
+{
+	h1=${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
+}
+
+multipath4_test()
+{
+	local what=$1; shift
+	local weight1=$1; shift
+	local weight2=$1; shift
+
+	sysctl_set net.ipv6.fib_multipath_hash_policy 2
+	ip route replace vrf v$ul21 2001:db8:40::2/128 \
+	   nexthop via 2001:db8:81::2 weight $weight1 \
+	   nexthop via 2001:db8:82::2 weight $weight2
+
+	local t0_111=$(tc_rule_stats_get $ul32 111 ingress)
+	local t0_222=$(tc_rule_stats_get $ul32 222 ingress)
+
+	ip vrf exec v$h1 \
+	   $MZ $h1 -q -p 64 -A "192.0.3.2-192.0.3.62" -B "192.0.4.2-192.0.4.62" \
+	       -d 1msec -c 50 -t udp "sp=1024,dp=1024"
+	sleep 1
+
+	local t1_111=$(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=$((t1_222 - t0_222))
+	multipath_eval "$what" $weight1 $weight2 $d111 $d222
+
+	ip route replace vrf v$ul21 2001:db8:40::2/128 \
+	   nexthop via 2001:db8:81::2 \
+	   nexthop via 2001:db8:82::2
+	sysctl_restore net.ipv6.fib_multipath_hash_policy
+}
+
+ping_ipv4()
+{
+	ping_test $h1 192.0.4.2
+}
+
+multipath_ipv4()
+{
+	log_info "Running IPv4 over GRE over IPv6 multipath tests"
+	multipath4_test "ECMP" 1 1
+	multipath4_test "Weighted MP 2:1" 2 1
+	multipath4_test "Weighted MP 11:45" 11 45
+}
+
+trap cleanup EXIT
+
+setup_prepare
+setup_wait
+tests_run
+
+exit $EXIT_STATUS
diff --git a/tools/testing/selftests/net/forwarding/ip6gre_inner_v6_multipath.sh b/tools/testing/selftests/net/forwarding/ip6gre_inner_v6_multipath.sh
new file mode 100755
index 000000000000..d208f5243ade
--- /dev/null
+++ b/tools/testing/selftests/net/forwarding/ip6gre_inner_v6_multipath.sh
@@ -0,0 +1,305 @@
+#!/bin/bash
+# SPDX-License-Identifier: GPL-2.0
+
+# Test traffic distribution when there are multiple routes between an IPv6
+# GRE tunnel. The tunnel carries 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 +     |
+# |  2001:db8:1::2/64 |     |
+# +-------------------|-----+
+#                     |
+# +-------------------|-------------------------+
+# | SW1               |                         |
+# |              $ol1 +                         |
+# |  2001:db8:1::1/64                           |
+# |                                             |
+# |  + g1 (gre)                                 |
+# |    loc=2001:db8:40::1                       |
+# |    rem=2001:db8:40::2 --.                   |
+# |    tos=inherit          |                   |
+# |                         v                   |
+# |                         + $ul1              |
+# |                         | 2001:db8:80::1/64 |
+# +-------------------------|-------------------+
+#                           |
+# +-------------------------|-------------------+
+# | SW2                     |                   |
+# |                   $ul21 +                   |
+# |       2001:db8:80::2/64                     |
+# |                   |                         |
+# !   ________________|_____                    |
+# |  /                      \                   |
+# |  |                      |                   |
+# |  + $ul22.111 (vlan)     + $ul22.222 (vlan)  |
+# |  | 2001:db8:81::1/64    | 2001:db8:82::1/64 |
+# |  |                      |                   |
+# +--|----------------------|-------------------+
+#    |                      |
+# +--|----------------------|-------------------+
+# |  |                      |                   |
+# |  + $ul32.111 (vlan)     + $ul32.222 (vlan)  |
+# |  | 2001:db8:81::2/64    | 2001:db8:82::2/64 |
+# |  |                      |                   |
+# |  \______________________/                   |
+# |                   |                         |
+# |                   |                         |
+# |                   $ul31 +                   |
+# |       2001:db8:83::2/64 |               SW3 |
+# +-------------------------|-------------------+
+#                           |
+# +-------------------------|-------------------+
+# |                         + $ul4              |
+# |                         ^ 2001:db8:83::1/64 |
+# |  + g2 (gre)             |                   |
+# |    loc=2001:db8:40::2   |                   |
+# |    rem=2001:db8:40::1 --'                   |
+# |    tos=inherit                              |
+# |                                             |
+# |               $ol4 +                        |
+# |   2001:db8:2::1/64 |                    SW4 |
+# +--------------------|------------------------+
+#                      |
+# +--------------------|---------+
+# |                    |         |
+# |                $h2 +         |
+# |   2001:db8:2::2/64        H2 |
+# +------------------------------+
+
+ALL_TESTS="
+	ping_ipv6
+	multipath_ipv6
+"
+
+NUM_NETIFS=10
+source lib.sh
+
+h1_create()
+{
+	simple_if_init $h1 2001:db8:1::2/64
+	ip -6 route add vrf v$h1 2001:db8:2::/64 via 2001:db8:1::1
+}
+
+h1_destroy()
+{
+	ip -6 route del vrf v$h1 2001:db8:2::/64 via 2001:db8:1::1
+	simple_if_fini $h1 2001:db8:1::2/64
+}
+
+sw1_create()
+{
+	simple_if_init $ol1 2001:db8:1::1/64
+	__simple_if_init $ul1 v$ol1 2001:db8:80::1/64
+
+	tunnel_create g1 ip6gre 2001:db8:40::1 2001:db8:40::2 tos inherit dev v$ol1
+	__simple_if_init g1 v$ol1 2001:db8:40::1/128
+	ip -6 route add vrf v$ol1 2001:db8:40::2/128 via 2001:db8:80::2
+
+	ip -6 route add vrf v$ol1 2001:db8:2::/64 dev g1
+}
+
+sw1_destroy()
+{
+	ip -6 route del vrf v$ol1 2001:db8:2::/64
+
+	ip -6 route del vrf v$ol1 2001:db8:40::2/128
+	__simple_if_fini g1 2001:db8:40::1/128
+	tunnel_destroy g1
+
+	__simple_if_fini $ul1 2001:db8:80::1/64
+	simple_if_fini $ol1 2001:db8:1::1/64
+}
+
+sw2_create()
+{
+	simple_if_init $ul21 2001:db8:80::2/64
+	__simple_if_init $ul22 v$ul21
+	vlan_create $ul22 111 v$ul21 2001:db8:81::1/64
+	vlan_create $ul22 222 v$ul21 2001:db8:82::1/64
+
+	ip -6 route add vrf v$ul21 2001:db8:40::1/128 via 2001:db8:80::1
+	ip -6 route add vrf v$ul21 2001:db8:40::2/128 \
+	   nexthop via 2001:db8:81::2 \
+	   nexthop via 2001:db8:82::2
+}
+
+sw2_destroy()
+{
+	ip -6 route del vrf v$ul21 2001:db8:40::2/128
+	ip -6 route del vrf v$ul21 2001:db8:40::1/128
+
+	vlan_destroy $ul22 222
+	vlan_destroy $ul22 111
+	__simple_if_fini $ul22
+	simple_if_fini $ul21 2001:db8:80::2/64
+}
+
+sw3_create()
+{
+	simple_if_init $ul31 2001:db8:83::2/64
+	__simple_if_init $ul32 v$ul31
+	vlan_create $ul32 111 v$ul31 2001:db8:81::2/64
+	vlan_create $ul32 222 v$ul31 2001:db8:82::2/64
+
+	ip -6 route add vrf v$ul31 2001:db8:40::2/128 via 2001:db8:83::1
+	ip -6 route add vrf v$ul31 2001:db8:40::1/128 \
+	   nexthop via 2001:db8:81::1 \
+	   nexthop via 2001:db8:82::1
+
+	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 $ul32 clsact
+
+	ip -6 route del vrf v$ul31 2001:db8:40::1/128
+	ip -6 route del vrf v$ul31 2001:db8:40::2/128
+
+	vlan_destroy $ul32 222
+	vlan_destroy $ul32 111
+	__simple_if_fini $ul32
+	simple_if_fini $ul31 2001:Db8:83::2/64
+}
+
+sw4_create()
+{
+	simple_if_init $ol4 2001:db8:2::1/64
+	__simple_if_init $ul4 v$ol4 2001:db8:83::1/64
+
+	tunnel_create g2 ip6gre 2001:db8:40::2 2001:db8:40::1 tos inherit dev v$ol4
+	__simple_if_init g2 v$ol4 2001:db8:40::2/128
+	ip -6 route add vrf v$ol4 2001:db8:40::1/128 via 2001:db8:83::2
+
+	ip -6 route add vrf v$ol4 2001:db8:1::/64 dev g2
+}
+
+sw4_destroy()
+{
+	ip -6 route del vrf v$ol4 2001:db8:1::/64
+
+	ip -6 route del vrf v$ol4 2001:db8:40::1/128
+	__simple_if_fini g2 2001:db8:40::2/128
+	tunnel_destroy g2
+
+	__simple_if_fini $ul4 2001:db8:83::1/64
+	simple_if_fini $ol4 2001:db8:2::1/64
+}
+
+h2_create()
+{
+	simple_if_init $h2 2001:db8:2::2/64
+	ip -6 route add vrf v$h2 2001:db8:1::/64 via 2001:db8:2::1
+}
+
+h2_destroy()
+{
+	ip -6 route del vrf v$h2 2001:db8:1::/64 via 2001:db8:2::1
+	simple_if_fini $h2 2001:db8:2::2/64
+}
+
+setup_prepare()
+{
+	h1=${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
+}
+
+multipath6_test()
+{
+	local what=$1; shift
+	local weight1=$1; shift
+	local weight2=$1; shift
+
+	sysctl_set net.ipv6.fib_multipath_hash_policy 2
+	ip route replace vrf v$ul21 2001:db8:40::2/128 \
+	   nexthop via 2001:db8:81::2 weight $weight1 \
+	   nexthop via 2001:db8:82::2 weight $weight2
+
+	local t0_111=$(tc_rule_stats_get $ul32 111 ingress)
+	local t0_222=$(tc_rule_stats_get $ul32 222 ingress)
+
+	ip vrf exec v$h1 \
+	   $MZ $h1 -6 -q -p 64 -A "2001:db8:1::2-2001:db8:1::1e" \
+	       -B "2001:db8:2::2-2001:db8:2::1e" \
+	       -d 1msec -c 50 -t udp "sp=1024,dp=1024"
+	sleep 1
+
+	local t1_111=$(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=$((t1_222 - t0_222))
+	multipath_eval "$what" $weight1 $weight2 $d111 $d222
+
+	ip route replace vrf v$ul21 2001:db8:40::2/128 \
+	   nexthop via 2001:db8:81::2 \
+	   nexthop via 2001:db8:82::2
+	sysctl_restore net.ipv6.fib_multipath_hash_policy
+}
+
+ping_ipv6()
+{
+	ping_test $h1 2001:db8:2::2
+}
+
+multipath_ipv6()
+{
+	log_info "Running IPv6 over GRE over IPv6 multipath tests"
+	multipath6_test "ECMP" 1 1
+	multipath6_test "Weighted MP 2:1" 2 1
+	multipath6_test "Weighted MP 11:45" 11 45
+}
+
+trap cleanup EXIT
+
+setup_prepare
+setup_wait
+tests_run
+
+exit $EXIT_STATUS