selftests: forwarding: Create test topology for multipath routing

Create a topology with two hosts, each directly connected to a different
router. Both routers are connected using two links, enabling multipath
routing.

Test IPv4 and IPv6 ping using default MTU and large MTU.
Signed-off-by: Ido Schimmel <idosch@mellanox.com>
Signed-off-by: David S. Miller <davem@davemloft.net>

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

+#!/bin/bash
+# SPDX-License-Identifier: GPL-2.0
+
+NUM_NETIFS=8
+source lib.sh
+
+h1_create()
+{
+	vrf_create "vrf-h1"
+	ip link set dev $h1 master vrf-h1
+
+	ip link set dev vrf-h1 up
+	ip link set dev $h1 up
+
+	ip address add 192.0.2.2/24 dev $h1
+	ip address add 2001:db8:1::2/64 dev $h1
+
+	ip route add 198.51.100.0/24 vrf vrf-h1 nexthop via 192.0.2.1
+	ip route add 2001:db8:2::/64 vrf vrf-h1 nexthop via 2001:db8:1::1
+}
+
+h1_destroy()
+{
+	ip route del 2001:db8:2::/64 vrf vrf-h1
+	ip route del 198.51.100.0/24 vrf vrf-h1
+
+	ip address del 2001:db8:1::2/64 dev $h1
+	ip address del 192.0.2.2/24 dev $h1
+
+	ip link set dev $h1 down
+	vrf_destroy "vrf-h1"
+}
+
+h2_create()
+{
+	vrf_create "vrf-h2"
+	ip link set dev $h2 master vrf-h2
+
+	ip link set dev vrf-h2 up
+	ip link set dev $h2 up
+
+	ip address add 198.51.100.2/24 dev $h2
+	ip address add 2001:db8:2::2/64 dev $h2
+
+	ip route add 192.0.2.0/24 vrf vrf-h2 nexthop via 198.51.100.1
+	ip route add 2001:db8:1::/64 vrf vrf-h2 nexthop via 2001:db8:2::1
+}
+
+h2_destroy()
+{
+	ip route del 2001:db8:1::/64 vrf vrf-h2
+	ip route del 192.0.2.0/24 vrf vrf-h2
+
+	ip address del 2001:db8:2::2/64 dev $h2
+	ip address del 198.51.100.2/24 dev $h2
+
+	ip link set dev $h2 down
+	vrf_destroy "vrf-h2"
+}
+
+router1_create()
+{
+	vrf_create "vrf-r1"
+	ip link set dev $rp11 master vrf-r1
+	ip link set dev $rp12 master vrf-r1
+	ip link set dev $rp13 master vrf-r1
+
+	ip link set dev vrf-r1 up
+	ip link set dev $rp11 up
+	ip link set dev $rp12 up
+	ip link set dev $rp13 up
+
+	ip address add 192.0.2.1/24 dev $rp11
+	ip address add 2001:db8:1::1/64 dev $rp11
+
+	ip address add 169.254.2.12/24 dev $rp12
+	ip address add fe80:2::12/64 dev $rp12
+
+	ip address add 169.254.3.13/24 dev $rp13
+	ip address add fe80:3::13/64 dev $rp13
+
+	ip route add 198.51.100.0/24 vrf vrf-r1 \
+		nexthop via 169.254.2.22 dev $rp12 \
+		nexthop via 169.254.3.23 dev $rp13
+	ip route add 2001:db8:2::/64 vrf vrf-r1 \
+		nexthop via fe80:2::22 dev $rp12 \
+		nexthop via fe80:3::23 dev $rp13
+}
+
+router1_destroy()
+{
+	ip route del 2001:db8:2::/64 vrf vrf-r1
+	ip route del 198.51.100.0/24 vrf vrf-r1
+
+	ip address del fe80:3::13/64 dev $rp13
+	ip address del 169.254.3.13/24 dev $rp13
+
+	ip address del fe80:2::12/64 dev $rp12
+	ip address del 169.254.2.12/24 dev $rp12
+
+	ip address del 2001:db8:1::1/64 dev $rp11
+	ip address del 192.0.2.1/24 dev $rp11
+
+	ip link set dev $rp13 down
+	ip link set dev $rp12 down
+	ip link set dev $rp11 down
+
+	vrf_destroy "vrf-r1"
+}
+
+router2_create()
+{
+	vrf_create "vrf-r2"
+	ip link set dev $rp21 master vrf-r2
+	ip link set dev $rp22 master vrf-r2
+	ip link set dev $rp23 master vrf-r2
+
+	ip link set dev vrf-r2 up
+	ip link set dev $rp21 up
+	ip link set dev $rp22 up
+	ip link set dev $rp23 up
+
+	ip address add 198.51.100.1/24 dev $rp21
+	ip address add 2001:db8:2::1/64 dev $rp21
+
+	ip address add 169.254.2.22/24 dev $rp22
+	ip address add fe80:2::22/64 dev $rp22
+
+	ip address add 169.254.3.23/24 dev $rp23
+	ip address add fe80:3::23/64 dev $rp23
+
+	ip route add 192.0.2.0/24 vrf vrf-r2 \
+		nexthop via 169.254.2.12 dev $rp22 \
+		nexthop via 169.254.3.13 dev $rp23
+	ip route add 2001:db8:1::/64 vrf vrf-r2 \
+		nexthop via fe80:2::12 dev $rp22 \
+		nexthop via fe80:3::13 dev $rp23
+}
+
+router2_destroy()
+{
+	ip route del 2001:db8:1::/64 vrf vrf-r2
+	ip route del 192.0.2.0/24 vrf vrf-r2
+
+	ip address del fe80:3::23/64 dev $rp23
+	ip address del 169.254.3.23/24 dev $rp23
+
+	ip address del fe80:2::22/64 dev $rp22
+	ip address del 169.254.2.22/24 dev $rp22
+
+	ip address del 2001:db8:2::1/64 dev $rp21
+	ip address del 198.51.100.1/24 dev $rp21
+
+	ip link set dev $rp23 down
+	ip link set dev $rp22 down
+	ip link set dev $rp21 down
+
+	vrf_destroy "vrf-r2"
+}
+
+setup_prepare()
+{
+	h1=${NETIFS[p1]}
+	rp11=${NETIFS[p2]}
+
+	rp12=${NETIFS[p3]}
+	rp22=${NETIFS[p4]}
+
+	rp13=${NETIFS[p5]}
+	rp23=${NETIFS[p6]}
+
+	rp21=${NETIFS[p7]}
+	h2=${NETIFS[p8]}
+
+	vrf_prepare
+
+	h1_create
+	h2_create
+
+	router1_create
+	router2_create
+
+	forwarding_enable
+}
+
+cleanup()
+{
+	pre_cleanup
+
+	forwarding_restore
+
+	router2_destroy
+	router1_destroy
+
+	h2_destroy
+	h1_destroy
+
+	vrf_cleanup
+}
+
+trap cleanup EXIT
+
+setup_prepare
+setup_wait
+
+ping_test $h1 198.51.100.2
+ping6_test $h1 2001:db8:2::2
+
+exit $EXIT_STATUS