diff --git a/tools/testing/selftests/net/forwarding/ethtool_extended_state.sh b/tools/testing/selftests/net/forwarding/ethtool_extended_state.sh
new file mode 100755
index 000000000000..4b42dfd4efd1
--- /dev/null
+++ b/tools/testing/selftests/net/forwarding/ethtool_extended_state.sh
@@ -0,0 +1,102 @@
+#!/bin/bash
+# SPDX-License-Identifier: GPL-2.0
+
+ALL_TESTS="
+	autoneg
+	autoneg_force_mode
+	no_cable
+"
+
+NUM_NETIFS=2
+source lib.sh
+source ethtool_lib.sh
+
+setup_prepare()
+{
+	swp1=${NETIFS[p1]}
+	swp2=${NETIFS[p2]}
+	swp3=$NETIF_NO_CABLE
+}
+
+ethtool_extended_state_check()
+{
+	local dev=$1; shift
+	local expected_ext_state=$1; shift
+	local expected_ext_substate=${1:-""}; shift
+
+	local ext_state=$(ethtool $dev | grep "Link detected" \
+		| cut -d "(" -f2 | cut -d ")" -f1)
+	local ext_substate=$(echo $ext_state | cut -sd "," -f2 \
+		| sed -e 's/^[[:space:]]*//')
+	ext_state=$(echo $ext_state | cut -d "," -f1)
+
+	[[ $ext_state == $expected_ext_state ]]
+	check_err $? "Expected \"$expected_ext_state\", got \"$ext_state\""
+
+	[[ $ext_substate == $expected_ext_substate ]]
+	check_err $? "Expected \"$expected_ext_substate\", got \"$ext_substate\""
+}
+
+autoneg()
+{
+	RET=0
+
+	ip link set dev $swp1 up
+
+	sleep 4
+	ethtool_extended_state_check $swp1 "Autoneg" "No partner detected"
+
+	log_test "Autoneg, No partner detected"
+
+	ip link set dev $swp1 down
+}
+
+autoneg_force_mode()
+{
+	RET=0
+
+	ip link set dev $swp1 up
+	ip link set dev $swp2 up
+
+	local -a speeds_arr=($(different_speeds_get $swp1 $swp2 0 0))
+	local speed1=${speeds_arr[0]}
+	local speed2=${speeds_arr[1]}
+
+	ethtool_set $swp1 speed $speed1 autoneg off
+	ethtool_set $swp2 speed $speed2 autoneg off
+
+	sleep 4
+	ethtool_extended_state_check $swp1 "Autoneg" \
+		"No partner detected during force mode"
+
+	ethtool_extended_state_check $swp2 "Autoneg" \
+		"No partner detected during force mode"
+
+	log_test "Autoneg, No partner detected during force mode"
+
+	ethtool -s $swp2 autoneg on
+	ethtool -s $swp1 autoneg on
+
+	ip link set dev $swp2 down
+	ip link set dev $swp1 down
+}
+
+no_cable()
+{
+	RET=0
+
+	ip link set dev $swp3 up
+
+	sleep 1
+	ethtool_extended_state_check $swp3 "No cable"
+
+	log_test "No cable"
+
+	ip link set dev $swp3 down
+}
+
+setup_prepare
+
+tests_run
+
+exit $EXIT_STATUS