netconsole: selftest: Split the helpers from the selftest

Split helper functions from the netconsole basic test into a separate
library file to enable reuse across different netconsole tests. This
change only moves the existing helper functions to lib/sh/lib_netcons.sh
while preserving the same test functionality.

The helpers provide common functions for:
- Setting up network namespaces and interfaces
- Managing netconsole dynamic targets
- Setting user data
- Handling test dependencies
- Cleanup operations

Do not make any change in the code, other than the mechanical
separation.

Signed-off-by: Breno Leitao <[email protected]>
Tested-by: Simon Horman <[email protected]>
Reviewed-by: Simon Horman <[email protected]>
Link: https://patch.msgid.link/[email protected]
Signed-off-by: Jakub Kicinski <[email protected]>

Author: leitao

MAINTAINERS

@@ -16170,6 +16170,7 @@ M:	Breno Leitao <[email protected]>
 S:	Maintained
 F:	Documentation/networking/netconsole.rst
 F:	drivers/net/netconsole.c
+F:	tools/testing/selftests/drivers/net/lib/sh/lib_netcons.sh
 F:	tools/testing/selftests/drivers/net/netcons_basic.sh
 
 NETDEVSIM

tools/testing/selftests/drivers/net/Makefile

@@ -1,6 +1,7 @@
 # SPDX-License-Identifier: GPL-2.0
 
 TEST_INCLUDES := $(wildcard lib/py/*.py) \
+		 $(wildcard lib/sh/*.sh) \
 		 ../../net/net_helper.sh \
 		 ../../net/lib.sh \
 

tools/testing/selftests/drivers/net/lib/sh/lib_netcons.sh

@@ -0,0 +1,225 @@
+#!/usr/bin/env bash
+# SPDX-License-Identifier: GPL-2.0
+
+# This file contains functions and helpers to support the netconsole
+# selftests
+#
+# Author: Breno Leitao <[email protected]>
+
+set -euo pipefail
+
+LIBDIR=$(dirname "$(readlink -e "${BASH_SOURCE[0]}")")
+
+SRCIF="" # to be populated later
+SRCIP=192.0.2.1
+DSTIF="" # to be populated later
+DSTIP=192.0.2.2
+
+PORT="6666"
+MSG="netconsole selftest"
+USERDATA_KEY="key"
+USERDATA_VALUE="value"
+TARGET=$(mktemp -u netcons_XXXXX)
+DEFAULT_PRINTK_VALUES=$(cat /proc/sys/kernel/printk)
+NETCONS_CONFIGFS="/sys/kernel/config/netconsole"
+NETCONS_PATH="${NETCONS_CONFIGFS}"/"${TARGET}"
+KEY_PATH="${NETCONS_PATH}/userdata/${USERDATA_KEY}"
+# NAMESPACE will be populated by setup_ns with a random value
+NAMESPACE=""
+
+# IDs for netdevsim
+NSIM_DEV_1_ID=$((256 + RANDOM % 256))
+NSIM_DEV_2_ID=$((512 + RANDOM % 256))
+NSIM_DEV_SYS_NEW="/sys/bus/netdevsim/new_device"
+
+# Used to create and delete namespaces
+source "${LIBDIR}"/../../../../net/lib.sh
+source "${LIBDIR}"/../../../../net/net_helper.sh
+
+# Create netdevsim interfaces
+create_ifaces() {
+
+	echo "$NSIM_DEV_2_ID" > "$NSIM_DEV_SYS_NEW"
+	echo "$NSIM_DEV_1_ID" > "$NSIM_DEV_SYS_NEW"
+	udevadm settle 2> /dev/null || true
+
+	local NSIM1=/sys/bus/netdevsim/devices/netdevsim"$NSIM_DEV_1_ID"
+	local NSIM2=/sys/bus/netdevsim/devices/netdevsim"$NSIM_DEV_2_ID"
+
+	# These are global variables
+	SRCIF=$(find "$NSIM1"/net -maxdepth 1 -type d ! \
+		-path "$NSIM1"/net -exec basename {} \;)
+	DSTIF=$(find "$NSIM2"/net -maxdepth 1 -type d ! \
+		-path "$NSIM2"/net -exec basename {} \;)
+}
+
+link_ifaces() {
+	local NSIM_DEV_SYS_LINK="/sys/bus/netdevsim/link_device"
+	local SRCIF_IFIDX=$(cat /sys/class/net/"$SRCIF"/ifindex)
+	local DSTIF_IFIDX=$(cat /sys/class/net/"$DSTIF"/ifindex)
+
+	exec {NAMESPACE_FD}</var/run/netns/"${NAMESPACE}"
+	exec {INITNS_FD}</proc/self/ns/net
+
+	# Bind the dst interface to namespace
+	ip link set "${DSTIF}" netns "${NAMESPACE}"
+
+	# Linking one device to the other one (on the other namespace}
+	if ! echo "${INITNS_FD}:$SRCIF_IFIDX $NAMESPACE_FD:$DSTIF_IFIDX"  > $NSIM_DEV_SYS_LINK
+	then
+		echo "linking netdevsim1 with netdevsim2 should succeed"
+		cleanup
+		exit "${ksft_skip}"
+	fi
+}
+
+function configure_ip() {
+	# Configure the IPs for both interfaces
+	ip netns exec "${NAMESPACE}" ip addr add "${DSTIP}"/24 dev "${DSTIF}"
+	ip netns exec "${NAMESPACE}" ip link set "${DSTIF}" up
+
+	ip addr add "${SRCIP}"/24 dev "${SRCIF}"
+	ip link set "${SRCIF}" up
+}
+
+function set_network() {
+	# setup_ns function is coming from lib.sh
+	setup_ns NAMESPACE
+
+	# Create both interfaces, and assign the destination to a different
+	# namespace
+	create_ifaces
+
+	# Link both interfaces back to back
+	link_ifaces
+
+	configure_ip
+}
+
+function create_dynamic_target() {
+	DSTMAC=$(ip netns exec "${NAMESPACE}" \
+		 ip link show "${DSTIF}" | awk '/ether/ {print $2}')
+
+	# Create a dynamic target
+	mkdir "${NETCONS_PATH}"
+
+	echo "${DSTIP}" > "${NETCONS_PATH}"/remote_ip
+	echo "${SRCIP}" > "${NETCONS_PATH}"/local_ip
+	echo "${DSTMAC}" > "${NETCONS_PATH}"/remote_mac
+	echo "${SRCIF}" > "${NETCONS_PATH}"/dev_name
+
+	echo 1 > "${NETCONS_PATH}"/enabled
+}
+
+function cleanup() {
+	local NSIM_DEV_SYS_DEL="/sys/bus/netdevsim/del_device"
+
+	# delete netconsole dynamic reconfiguration
+	echo 0 > "${NETCONS_PATH}"/enabled
+	# Remove key
+	rmdir "${KEY_PATH}"
+	# Remove the configfs entry
+	rmdir "${NETCONS_PATH}"
+
+	# Delete netdevsim devices
+	echo "$NSIM_DEV_2_ID" > "$NSIM_DEV_SYS_DEL"
+	echo "$NSIM_DEV_1_ID" > "$NSIM_DEV_SYS_DEL"
+
+	# this is coming from lib.sh
+	cleanup_all_ns
+
+	# Restoring printk configurations
+	echo "${DEFAULT_PRINTK_VALUES}" > /proc/sys/kernel/printk
+}
+
+function set_user_data() {
+	if [[ ! -d "${NETCONS_PATH}""/userdata" ]]
+	then
+		echo "Userdata path not available in ${NETCONS_PATH}/userdata"
+		exit "${ksft_skip}"
+	fi
+
+	mkdir -p "${KEY_PATH}"
+	VALUE_PATH="${KEY_PATH}""/value"
+	echo "${USERDATA_VALUE}" > "${VALUE_PATH}"
+}
+
+function listen_port_and_save_to() {
+	local OUTPUT=${1}
+	# Just wait for 2 seconds
+	timeout 2 ip netns exec "${NAMESPACE}" \
+		socat UDP-LISTEN:"${PORT}",fork "${OUTPUT}"
+}
+
+function validate_result() {
+	local TMPFILENAME="$1"
+
+	# TMPFILENAME will contain something like:
+	# 6.11.1-0_fbk0_rc13_509_g30d75cea12f7,13,1822,115075213798,-;netconsole selftest: netcons_gtJHM
+	#  key=value
+
+	# Check if the file exists
+	if [ ! -f "$TMPFILENAME" ]; then
+		echo "FAIL: File was not generated." >&2
+		exit "${ksft_fail}"
+	fi
+
+	if ! grep -q "${MSG}" "${TMPFILENAME}"; then
+		echo "FAIL: ${MSG} not found in ${TMPFILENAME}" >&2
+		cat "${TMPFILENAME}" >&2
+		exit "${ksft_fail}"
+	fi
+
+	if ! grep -q "${USERDATA_KEY}=${USERDATA_VALUE}" "${TMPFILENAME}"; then
+		echo "FAIL: ${USERDATA_KEY}=${USERDATA_VALUE} not found in ${TMPFILENAME}" >&2
+		cat "${TMPFILENAME}" >&2
+		exit "${ksft_fail}"
+	fi
+
+	# Delete the file once it is validated, otherwise keep it
+	# for debugging purposes
+	rm "${TMPFILENAME}"
+	exit "${ksft_pass}"
+}
+
+function check_for_dependencies() {
+	if [ "$(id -u)" -ne 0 ]; then
+		echo "This test must be run as root" >&2
+		exit "${ksft_skip}"
+	fi
+
+	if ! which socat > /dev/null ; then
+		echo "SKIP: socat(1) is not available" >&2
+		exit "${ksft_skip}"
+	fi
+
+	if ! which ip > /dev/null ; then
+		echo "SKIP: ip(1) is not available" >&2
+		exit "${ksft_skip}"
+	fi
+
+	if ! which udevadm > /dev/null ; then
+		echo "SKIP: udevadm(1) is not available" >&2
+		exit "${ksft_skip}"
+	fi
+
+	if [ ! -f "${NSIM_DEV_SYS_NEW}" ]; then
+		echo "SKIP: file ${NSIM_DEV_SYS_NEW} does not exist. Check if CONFIG_NETDEVSIM is enabled" >&2
+		exit "${ksft_skip}"
+	fi
+
+	if [ ! -d "${NETCONS_CONFIGFS}" ]; then
+		echo "SKIP: directory ${NETCONS_CONFIGFS} does not exist. Check if NETCONSOLE_DYNAMIC is enabled" >&2
+		exit "${ksft_skip}"
+	fi
+
+	if ip link show "${DSTIF}" 2> /dev/null; then
+		echo "SKIP: interface ${DSTIF} exists in the system. Not overwriting it." >&2
+		exit "${ksft_skip}"
+	fi
+
+	if ip addr list | grep -E "inet.*(${SRCIP}|${DSTIP})" 2> /dev/null; then
+		echo "SKIP: IPs already in use. Skipping it" >&2
+		exit "${ksft_skip}"
+	fi
+}