1 files changed, 111 insertions, 0 deletions
diff --git a/tools/testing/selftests/net/lib/ksft_setup_loopback.sh b/tools/testing/selftests/net/lib/ksft_setup_loopback.sh
new file mode 100755
index 000000000000..3defbb1919c5
--- /dev/null
+++ b/tools/testing/selftests/net/lib/ksft_setup_loopback.sh
@@ -0,0 +1,111 @@
+#!/bin/bash
+# SPDX-License-Identifier: GPL-2.0
+
+# Setup script for running ksft tests over a real interface in loopback mode.
+# This scripts replaces the historical setup_loopback.sh. It puts
+# a (presumably) real hardware interface into loopback mode, creates macvlan
+# interfaces on top and places them in a network namespace for isolation.
+#
+# NETIF env variable must be exported to indicate the real target device.
+# Note that the test will override NETIF with one of the macvlans, the
+# actual ksft test will only see the macvlans.
+#
+# Example use:
+#   export NETIF=eth0
+#   ./net/lib/ksft_setup_loopback.sh ./drivers/net/gro.py
+
+if [ -z "$NETIF" ]; then
+    echo "Error: NETIF variable not set"
+    exit 1
+fi
+if ! [ -d "/sys/class/net/$NETIF" ]; then
+    echo "Error: Can't find $NETIF, invalid netdevice"
+    exit 1
+fi
+
+# Save original settings for cleanup
+readonly FLUSH_PATH="/sys/class/net/${NETIF}/gro_flush_timeout"
+readonly IRQ_PATH="/sys/class/net/${NETIF}/napi_defer_hard_irqs"
+FLUSH_TIMEOUT="$(< "${FLUSH_PATH}")"
+readonly FLUSH_TIMEOUT
+HARD_IRQS="$(< "${IRQ_PATH}")"
+readonly HARD_IRQS
+
+SERVER_NS=$(mktemp -u server-XXXXXXXX)
+readonly SERVER_NS
+CLIENT_NS=$(mktemp -u client-XXXXXXXX)
+readonly CLIENT_NS
+readonly SERVER_MAC="aa:00:00:00:00:02"
+readonly CLIENT_MAC="aa:00:00:00:00:01"
+
+# ksft expects addresses to communicate with remote
+export  LOCAL_V6=2001:db8:1::1
+export REMOTE_V6=2001:db8:1::2
+
+cleanup() {
+    local exit_code=$?
+
+    echo "Cleaning up..."
+
+    # Remove macvlan interfaces and namespaces
+    ip -netns "${SERVER_NS}" link del dev server 2>/dev/null || true
+    ip netns del "${SERVER_NS}" 2>/dev/null || true
+    ip -netns "${CLIENT_NS}" link del dev client 2>/dev/null || true
+    ip netns del "${CLIENT_NS}" 2>/dev/null || true
+
+    # Disable loopback
+    ethtool -K "${NETIF}" loopback off 2>/dev/null || true
+    sleep 1
+
+    echo "${FLUSH_TIMEOUT}" >"${FLUSH_PATH}"
+    echo "${HARD_IRQS}" >"${IRQ_PATH}"
+
+    exit $exit_code
+}
+
+trap cleanup EXIT INT TERM
+
+# Enable loopback mode
+echo "Enabling loopback on ${NETIF}..."
+ethtool -K "${NETIF}" loopback on || {
+    echo "Failed to enable loopback mode"
+    exit 1
+}
+# The interface may need time to get carrier back, but selftests
+# will wait for carrier, so no need to wait / sleep here.
+
+# Use timer on  host to trigger the network stack
+# Also disable device interrupt to not depend on NIC interrupt
+# Reduce test flakiness caused by unexpected interrupts
+echo 100000 >"${FLUSH_PATH}"
+echo 50 >"${IRQ_PATH}"
+
+# Create server namespace with macvlan
+ip netns add "${SERVER_NS}"
+ip link add link "${NETIF}" dev server address "${SERVER_MAC}" type macvlan
+ip link set dev server netns "${SERVER_NS}"
+ip -netns "${SERVER_NS}" link set dev server up
+ip -netns "${SERVER_NS}" addr add $LOCAL_V6/64 dev server
+ip -netns "${SERVER_NS}" link set dev lo up
+
+# Create client namespace with macvlan
+ip netns add "${CLIENT_NS}"
+ip link add link "${NETIF}" dev client address "${CLIENT_MAC}" type macvlan
+ip link set dev client netns "${CLIENT_NS}"
+ip -netns "${CLIENT_NS}" link set dev client up
+ip -netns "${CLIENT_NS}" addr add $REMOTE_V6/64 dev client
+ip -netns "${CLIENT_NS}" link set dev lo up
+
+echo "Setup complete!"
+echo "  Device: ${NETIF}"
+echo "  Server NS: ${SERVER_NS}"
+echo "  Client NS: ${CLIENT_NS}"
+echo ""
+
+# Setup environment variables for tests
+export NETIF=server
+export REMOTE_TYPE=netns
+export REMOTE_ARGS="${CLIENT_NS}"
+
+# Run the command
+ip netns exec "${SERVER_NS}" "$@"