selftests: forwarding: Allow lib.sh sourcing from other directories

The devlink related scripts are mlxsw-specific. As a result, they'll
reside in a different directory - but would still need the common logic
implemented in lib.sh.
So as a preliminary step, allow lib.sh to be sourced from other
directories as well.
Signed-off-by: Yuval Mintz <yuvalm@mellanox.com>
Signed-off-by: Petr Machata <petrm@mellanox.com>
Signed-off-by: David S. Miller <davem@davemloft.net>

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

@@ -14,8 +14,13 @@ PAUSE_ON_CLEANUP=${PAUSE_ON_CLEANUP:=no}
 NETIF_TYPE=${NETIF_TYPE:=veth}
 NETIF_CREATE=${NETIF_CREATE:=yes}
 
-if [[ -f forwarding.config ]]; then
-	source forwarding.config
+relative_path="${BASH_SOURCE%/*}"
+if [[ "$relative_path" == "${BASH_SOURCE}" ]]; then
+	relative_path="."
+fi
+
+if [[ -f $relative_path/forwarding.config ]]; then
+	source "$relative_path/forwarding.config"
 fi
 
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