selftests: forwarding: Use sysctl_set(), sysctl_restore()

Instead of hand-managing the sysctl set and restore, use the wrappers
sysctl_set() and sysctl_restore() to do the bookkeeping automatically.

Signed-off-by: Petr Machata <petrm@mellanox.com>
Reviewed-by: Ido Schimmel <idosch@mellanox.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
diff --git a/tools/testing/selftests/net/forwarding/lib.sh b/tools/testing/selftests/net/forwarding/lib.sh
index e49e78b..91041c4 100644
--- a/tools/testing/selftests/net/forwarding/lib.sh
+++ b/tools/testing/selftests/net/forwarding/lib.sh
@@ -400,17 +400,14 @@
 
 forwarding_enable()
 {
-       ipv4_fwd=$(sysctl -n net.ipv4.conf.all.forwarding)
-       ipv6_fwd=$(sysctl -n net.ipv6.conf.all.forwarding)
-
-       sysctl -q -w net.ipv4.conf.all.forwarding=1
-       sysctl -q -w net.ipv6.conf.all.forwarding=1
+	sysctl_set net.ipv4.conf.all.forwarding 1
+	sysctl_set net.ipv6.conf.all.forwarding 1
 }
 
 forwarding_restore()
 {
-       sysctl -q -w net.ipv6.conf.all.forwarding=$ipv6_fwd
-       sysctl -q -w net.ipv4.conf.all.forwarding=$ipv4_fwd
+	sysctl_restore net.ipv6.conf.all.forwarding
+	sysctl_restore net.ipv4.conf.all.forwarding
 }
 
 tc_offload_check()