selftests: forwarding: Add multipath test for L4 hashing

Add IPv6 multipath test using L4 hashing. Created with inputs from
Ido Schimmel.
Signed-off-by: David Ahern <dsahern@gmail.com>
Reviewed-by: Ido Schimmel <idosch@mellanox.com>
Tested-by: Ido Schimmel <idosch@mellanox.com>
Signed-off-by: David S. Miller <davem@davemloft.net>

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

@@ -235,6 +235,45 @@ multipath4_test()
        sysctl -q -w net.ipv4.fib_multipath_hash_policy=$hash_policy
 }
 
+multipath6_l4_test()
+{
+       local desc="$1"
+       local weight_rp12=$2
+       local weight_rp13=$3
+       local t0_rp12 t0_rp13 t1_rp12 t1_rp13
+       local packets_rp12 packets_rp13
+       local hash_policy
+
+       # Transmit multiple flows from h1 to h2 and make sure they are
+       # distributed between both multipath links (rp12 and rp13)
+       # according to the configured weights.
+       hash_policy=$(sysctl -n net.ipv6.fib_multipath_hash_policy)
+       sysctl -q -w net.ipv6.fib_multipath_hash_policy=1
+
+       ip route replace 2001:db8:2::/64 vrf vrf-r1 \
+	       nexthop via fe80:2::22 dev $rp12 weight $weight_rp12 \
+	       nexthop via fe80:3::23 dev $rp13 weight $weight_rp13
+
+       t0_rp12=$(link_stats_tx_packets_get $rp12)
+       t0_rp13=$(link_stats_tx_packets_get $rp13)
+
+       $MZ $h1 -6 -q -p 64 -A 2001:db8:1::2 -B 2001:db8:2::2 \
+	       -d 1msec -t udp "sp=1024,dp=0-32768"
+
+       t1_rp12=$(link_stats_tx_packets_get $rp12)
+       t1_rp13=$(link_stats_tx_packets_get $rp13)
+
+       let "packets_rp12 = $t1_rp12 - $t0_rp12"
+       let "packets_rp13 = $t1_rp13 - $t0_rp13"
+       multipath_eval "$desc" $weight_rp12 $weight_rp13 $packets_rp12 $packets_rp13
+
+       ip route replace 2001:db8:2::/64 vrf vrf-r1 \
+	       nexthop via fe80:2::22 dev $rp12 \
+	       nexthop via fe80:3::23 dev $rp13
+
+       sysctl -q -w net.ipv6.fib_multipath_hash_policy=$hash_policy
+}
+
 multipath6_test()
 {
        local desc="$1"
@@ -278,6 +317,11 @@ multipath_test()
 	multipath6_test "ECMP" 1 1
 	multipath6_test "Weighted MP 2:1" 2 1
 	multipath6_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()