net: add large ecmp group nexthop tests

Add a couple large ecmp group nexthop selftests to cover
the remnant fixed by d69100b8eee27c2d60ee52df76e0b80a8d492d34.

The tests create 100 x32 ecmp groups of ipv4 and ipv6 and then
dump them. On kernels without the fix, they will fail due
to data remnant during the dump.

Signed-off-by: Stephen Worley <[e-mail]>
Reviewed-by: David Ahern <[e-mail]>
Reviewed-by: David Ahern <[e-mail]>
Signed-off-by: David S. Miller <[e-mail]>

tools/testing/selftests/net/fib_nexthops.sh

···
 ksft_skip=4
 
 # all tests in this script. Can be overridden with -t option
-IPV4_TESTS="ipv4_fcnal ipv4_grp_fcnal ipv4_withv6_fcnal ipv4_fcnal_runtime ipv4_compat_mode ipv4_fdb_grp_fcnal"
-IPV6_TESTS="ipv6_fcnal ipv6_grp_fcnal ipv6_fcnal_runtime ipv6_compat_mode ipv6_fdb_grp_fcnal"
+IPV4_TESTS="ipv4_fcnal ipv4_grp_fcnal ipv4_withv6_fcnal ipv4_fcnal_runtime ipv4_large_grp ipv4_compat_mode ipv4_fdb_grp_fcnal"
+IPV6_TESTS="ipv6_fcnal ipv6_grp_fcnal ipv6_fcnal_runtime ipv6_large_grp ipv6_compat_mode ipv6_fdb_grp_fcnal"
 
 ALL_TESTS="basic ${IPV4_TESTS} ${IPV6_TESTS}"
 TESTS="${ALL_TESTS}"
···
 	out=$($IP -6 route ls match ${pfx} 2>/dev/null | sed -e 's/pref medium//')
 
 	check_output "${out}" "${expected}"
+}
+
+check_large_grp()
+{
+	local ipv=$1
+	local ecmp=$2
+	local grpnum=100
+	local nhidstart=100
+	local grpidstart=1000
+	local iter=0
+	local nhidstr=""
+	local grpidstr=""
+	local grpstr=""
+	local ipstr=""
+
+	if [ $ipv -eq 4 ]; then
+		ipstr="172.16.1."
+	else
+		ipstr="2001:db8:91::"
+	fi
+
+	#
+	# Create $grpnum groups with specified $ecmp and dump them
+	#
+
+	# create nexthops with different gateways
+	iter=2
+	while [ $iter -le $(($ecmp + 1)) ]
+	do
+		nhidstr="$(($nhidstart + $iter))"
+		run_cmd "$IP nexthop add id $nhidstr via $ipstr$iter dev veth1"
+		check_nexthop "id $nhidstr" "id $nhidstr via $ipstr$iter dev veth1 scope link"
+
+		if [ $iter -le $ecmp ]; then
+			grpstr+="$nhidstr/"
+		else
+			grpstr+="$nhidstr"
+		fi
+		((iter++))
+	done
+
+	# create duplicate large ecmp groups
+	iter=0
+	while [ $iter -le $grpnum ]
+	do
+		grpidstr="$(($grpidstart + $iter))"
+		run_cmd "$IP nexthop add id $grpidstr group $grpstr"
+		check_nexthop "id $grpidstr" "id $grpidstr group $grpstr"
+		((iter++))
+	done
+
+	# dump large groups
+	run_cmd "$IP nexthop list"
+	log_test $? 0 "Dump large (x$ecmp) ecmp groups"
 }
 
 start_ip_monitor()
···
 	# route with src address and using nexthop - not allowed
 }
 
+ipv6_large_grp()
+{
+	local ecmp=32
+
+	echo
+	echo "IPv6 large groups (x$ecmp)"
+	echo "---------------------"
+
+	check_large_grp 6 $ecmp
+
+	$IP nexthop flush >/dev/null 2>&1
+}
+
 ipv4_fcnal()
 {
 	local rc
···
 	log_test $? 0 "IPv4 route with MPLS encap and v6 gateway"
 	check_nexthop "id 52" "id 52 encap mpls 102 via 2001:db8:91::2 dev veth1 scope link"
 	log_test $? 0 "IPv4 route with MPLS encap, v6 gw - check"
+}
+
+ipv4_large_grp()
+{
+	local ecmp=32
+
+	echo
+	echo "IPv4 large groups (x$ecmp)"
+	echo "---------------------"
+
+	check_large_grp 4 $ecmp
+
+	$IP nexthop flush >/dev/null 2>&1
 }
 
 sysctl_nexthop_compat_mode_check()