diff --git a/tools/testing/selftests/net/lib.sh b/tools/testing/selftests/net/lib.sh
new file mode 100755
index 0000000000000000000000000000000000000000..af5f0c82bf4dacbb656b1829ededebc6b174a389
--- /dev/null
+++ b/tools/testing/selftests/net/lib.sh
@@ -0,0 +1,92 @@
+#!/bin/bash
+# SPDX-License-Identifier: GPL-2.0
+
+##############################################################################
+# Defines
+
+WAIT_TIMEOUT=${WAIT_TIMEOUT:=20}
+BUSYWAIT_TIMEOUT=$((WAIT_TIMEOUT * 1000)) # ms
+
+# Kselftest framework requirement - SKIP code is 4.
+ksft_skip=4
+# namespace list created by setup_ns
+NS_LIST=()
+
+##############################################################################
+# Helpers
+busywait()
+{
+	local timeout=$1; shift
+
+	local start_time="$(date -u +%s%3N)"
+	while true
+	do
+		local out
+		if out=$("$@"); then
+			echo -n "$out"
+			return 0
+		fi
+
+		local current_time="$(date -u +%s%3N)"
+		if ((current_time - start_time > timeout)); then
+			echo -n "$out"
+			return 1
+		fi
+	done
+}
+
+cleanup_ns()
+{
+	local ns=""
+	local ret=0
+
+	for ns in "$@"; do
+		[ -z "${ns}" ] && continue
+		ip netns pids "${ns}" 2> /dev/null | xargs -r kill || true
+		ip netns delete "${ns}" &> /dev/null || true
+		if ! busywait $BUSYWAIT_TIMEOUT ip netns list \| grep -vq "^$ns$" &> /dev/null; then
+			echo "Warn: Failed to remove namespace $ns"
+			ret=1
+		fi
+	done
+
+	return $ret
+}
+
+cleanup_all_ns()
+{
+	cleanup_ns "${NS_LIST[@]}"
+}
+
+# setup netns with given names as prefix. e.g
+# setup_ns local remote
+setup_ns()
+{
+	local ns=""
+	local ns_name=""
+	local ns_list=()
+	local ns_exist=
+	for ns_name in "$@"; do
+		# Some test may setup/remove same netns multi times
+		if unset ${ns_name} 2> /dev/null; then
+			ns="${ns_name,,}-$(mktemp -u XXXXXX)"
+			eval readonly ${ns_name}="$ns"
+			ns_exist=false
+		else
+			eval ns='$'${ns_name}
+			cleanup_ns "$ns"
+			ns_exist=true
+		fi
+
+		if ! ip netns add "$ns"; then
+			echo "Failed to create namespace $ns_name"
+			cleanup_ns "${ns_list[@]}"
+			return $ksft_skip
+		fi
+		ip -n "$ns" link set lo up
+		ip netns exec "${!ns_name}" sysctl -wq net.ipv4.conf.all.rp_filter=0
+		ip netns exec "${!ns_name}" sysctl -wq net.ipv4.conf.default.rp_filter=0
+		! $ns_exist && ns_list+=("$ns")
+	done
+	NS_LIST+=("${ns_list[@]}")
+}
diff --git a/tools/testing/selftests/net/pmtu.sh b/tools/testing/selftests/net/pmtu.sh
index 771f237c43534e3bf309ffd3b39d89b25b36ee50..60cc52f64624734f5026ccde9628c9d1ae556cf1 100755
--- a/tools/testing/selftests/net/pmtu.sh
+++ b/tools/testing/selftests/net/pmtu.sh
@@ -204,8 +204,8 @@
 #	addresses have multipath routes to each other, b_r1 mtu = 1500.
 #	Check that PMTU exceptions are created for both paths.
 
-source lib.sh
-source net_helper.sh
+source ./lib.sh
+source ./net_helper.sh
 
 PAUSE_ON_FAIL=no
 VERBOSE=0
diff --git a/tools/testing/selftests/net/test_bridge_neigh_suppress.sh b/tools/testing/selftests/net/test_bridge_neigh_suppress.sh
index 02b986c9c247d6eb840d913c4a6b26db38cd01a1..9e35a2e747f4764e6c8c03ac98c7ef63116f837a 100755
--- a/tools/testing/selftests/net/test_bridge_neigh_suppress.sh
+++ b/tools/testing/selftests/net/test_bridge_neigh_suppress.sh
@@ -45,7 +45,7 @@
 # | sw1                                | | sw2                                |
 # +------------------------------------+ +------------------------------------+
 
-source lib.sh
+source ./lib.sh
 ret=0
 
 # All tests in this script. Can be overridden with -t option.
diff --git a/tools/testing/selftests/net/unicast_extensions.sh b/tools/testing/selftests/net/unicast_extensions.sh
index f52aa5f7da524098b3314a38b1a9b48117f5cd83..2766990c2b78f4b65872244d4d7f7a22c506023d 100755
--- a/tools/testing/selftests/net/unicast_extensions.sh
+++ b/tools/testing/selftests/net/unicast_extensions.sh
@@ -28,7 +28,7 @@
 # These tests provide an easy way to flip the expected result of any
 # of these behaviors for testing kernel patches that change them.
 
-source lib.sh
+source ./lib.sh
 
 # nettest can be run from PATH or from same directory as this selftest
 if ! which nettest >/dev/null; then