selftest: netcons: add test for netconsole over bonded interfaces

This patch adds a selftest that verifies netconsole functionality
over bonded network interfaces using netdevsim. It sets up two bonded
interfaces acting as transmit (TX) and receive (RX) ends, placed in
separate network namespaces. The test sends kernel log messages and
verifies that they are properly received on the bonded RX interfaces
with both IPv4 and IPv6, and using basic and extended netconsole
formats.

This patchset aims to test a long-standing netpoll subsystem where
netpoll has multiple users. (in this case netconsole and bonding). A
similar selftest has been discussed in [1] and [2].

This test also tries to enable bonding and netpoll in different order,
just to guarantee that all the possibilities are exercised.

Link: https://lore.kernel.org/all/[e-mail]/ [1]
Link: https://lore.kernel.org/lkml/[e-mail]/ [2]
Signed-off-by: Breno Leitao <[e-mail]>
Reviewed-by: Simon Horman <[e-mail]>
Link: https://patch.msgid.link/[e-mail]
Signed-off-by: Jakub Kicinski <[e-mail]>

tools/testing/selftests/drivers/net/bonding/Makefile

···
 	dev_addr_lists.sh \
 	mode-1-recovery-updelay.sh \
 	mode-2-recovery-updelay.sh \
+	netcons_over_bonding.sh \
 # end of TEST_PROGS
 
 TEST_FILES := \
···
 
 TEST_INCLUDES := \
 	../../../net/lib.sh \
+	../lib/sh/lib_netcons.sh \
 	../../../net/forwarding/lib.sh \
 # end of TEST_INCLUDES
 

tools/testing/selftests/drivers/net/bonding/config

···
 CONFIG_BONDING=y
 CONFIG_BRIDGE=y
+CONFIG_CONFIGFS_FS=y
 CONFIG_DUMMY=y
 CONFIG_INET_ESP=y
 CONFIG_INET_ESP_OFFLOAD=y
···
 CONFIG_NET_ACT_GACT=y
 CONFIG_NET_CLS_FLOWER=y
 CONFIG_NET_CLS_MATCHALL=m
+CONFIG_NETCONSOLE=m
+CONFIG_NETCONSOLE_DYNAMIC=y
+CONFIG_NETCONSOLE_EXTENDED_LOG=y
 CONFIG_NETDEVSIM=m
 CONFIG_NET_SCH_INGRESS=y
 CONFIG_NLMON=y

tools/testing/selftests/drivers/net/bonding/netcons_over_bonding.sh

···
+#!/usr/bin/env bash
+# SPDX-License-Identifier: GPL-2.0
+#
+# This selftest exercises trying to have multiple netpoll users at the same
+# time.
+#
+# This selftest has multiple smalls test inside, and the goal is to
+# get interfaces with bonding and netconsole in different orders in order
+# to catch any possible issue.
+#
+# The main test composes of four interfaces being created using netdevsim; two
+# of them are bonded to serve as the netconsole's transmit interface. The
+# remaining two interfaces are similarly bonded and assigned to a separate
+# network namespace, which acts as the receive interface, where socat monitors
+# for incoming messages.
+#
+# A netconsole message is then sent to ensure it is properly received across
+# this configuration.
+#
+# Later, run a few other tests, to make sure that bonding and netconsole
+# cannot coexist.
+#
+# The test's objective is to exercise netpoll usage when managed simultaneously
+# by multiple subsystems (netconsole and bonding).
+#
+# Author: Breno Leitao <[e-mail]>
+
+set -euo pipefail
+
+SCRIPTDIR=$(dirname "$(readlink -e "${BASH_SOURCE[0]}")")
+
+source "${SCRIPTDIR}"/../lib/sh/lib_netcons.sh
+
+modprobe netdevsim 2> /dev/null || true
+modprobe netconsole 2> /dev/null || true
+modprobe bonding 2> /dev/null || true
+modprobe veth 2> /dev/null || true
+
+# The content of kmsg will be save to the following file
+OUTPUT_FILE="/tmp/${TARGET}"
+
+# Check for basic system dependency and exit if not found
+check_for_dependencies
+# Set current loglevel to KERN_INFO(6), and default to KERN_NOTICE(5)
+echo "6 5" > /proc/sys/kernel/printk
+# Remove the namespace, interfaces and netconsole target on exit
+trap cleanup_bond EXIT
+
+FORMAT="extended"
+IP_VERSION="ipv4"
+VETH0="veth"$(( RANDOM % 256))
+VETH1="veth"$((256 +  RANDOM % 256))
+TXNS=""
+RXNS=""
+
+# Create "bond_tx_XX" and "bond_rx_XX" interfaces, and set DSTIF and SRCIF with
+# the bonding interfaces
+function setup_bonding_ifaces() {
+	local RAND=$(( RANDOM % 100 ))
+	BOND_TX_MAIN_IF="bond_tx_$RAND"
+	BOND_RX_MAIN_IF="bond_rx_$RAND"
+
+	# Setup TX
+	if ! ip -n "${TXNS}" link add "${BOND_TX_MAIN_IF}" type bond mode balance-rr
+	then
+		echo "Failed to create bond TX interface. Is CONFIG_BONDING set?" >&2
+		# only clean nsim ifaces and namespace. Nothing else has been
+		# initialized
+		cleanup_bond_nsim
+		trap - EXIT
+		exit "${ksft_skip}"
+	fi
+
+	# create_netdevsim() got the interface up, but it needs to be down
+	# before being enslaved.
+	ip -n "${TXNS}" \
+		link set "${BOND_TX1_SLAVE_IF}" down
+	ip -n "${TXNS}" \
+		link set "${BOND_TX2_SLAVE_IF}" down
+	ip -n "${TXNS}" \
+		link set "${BOND_TX1_SLAVE_IF}" master "${BOND_TX_MAIN_IF}"
+	ip -n "${TXNS}" \
+		link set "${BOND_TX2_SLAVE_IF}" master "${BOND_TX_MAIN_IF}"
+	ip -n "${TXNS}" \
+		link set "${BOND_TX_MAIN_IF}" up
+
+	# Setup RX
+	ip -n "${RXNS}" \
+		link add "${BOND_RX_MAIN_IF}" type bond mode balance-rr
+	ip -n "${RXNS}" \
+		link set "${BOND_RX1_SLAVE_IF}" down
+	ip -n "${RXNS}" \
+		link set "${BOND_RX2_SLAVE_IF}" down
+	ip -n "${RXNS}" \
+		link set "${BOND_RX1_SLAVE_IF}" master "${BOND_RX_MAIN_IF}"
+	ip -n "${RXNS}" \
+		link set "${BOND_RX2_SLAVE_IF}" master "${BOND_RX_MAIN_IF}"
+	ip -n "${RXNS}" \
+		link set "${BOND_RX_MAIN_IF}" up
+
+	export DSTIF="${BOND_RX_MAIN_IF}"
+	export SRCIF="${BOND_TX_MAIN_IF}"
+}
+
+# Create 4 netdevsim interfaces. Two of them will be bound to TX bonding iface
+# and the other two will be bond to the RX interface (on the other namespace)
+function create_ifaces_bond() {
+	BOND_TX1_SLAVE_IF=$(create_netdevsim "${NSIM_BOND_TX_1}" "${TXNS}")
+	BOND_TX2_SLAVE_IF=$(create_netdevsim "${NSIM_BOND_TX_2}" "${TXNS}")
+	BOND_RX1_SLAVE_IF=$(create_netdevsim "${NSIM_BOND_RX_1}" "${RXNS}")
+	BOND_RX2_SLAVE_IF=$(create_netdevsim "${NSIM_BOND_RX_2}" "${RXNS}")
+}
+
+# netdevsim link BOND_TX to BOND_RX interfaces
+function link_ifaces_bond() {
+	local BOND_TX1_SLAVE_IFIDX
+	local BOND_TX2_SLAVE_IFIDX
+	local BOND_RX1_SLAVE_IFIDX
+	local BOND_RX2_SLAVE_IFIDX
+	local TXNS_FD
+	local RXNS_FD
+
+	BOND_TX1_SLAVE_IFIDX=$(ip netns exec "${TXNS}" \
+				cat /sys/class/net/"$BOND_TX1_SLAVE_IF"/ifindex)
+	BOND_TX2_SLAVE_IFIDX=$(ip netns exec "${TXNS}" \
+				cat /sys/class/net/"$BOND_TX2_SLAVE_IF"/ifindex)
+	BOND_RX1_SLAVE_IFIDX=$(ip netns exec "${RXNS}" \
+				cat /sys/class/net/"$BOND_RX1_SLAVE_IF"/ifindex)
+	BOND_RX2_SLAVE_IFIDX=$(ip netns exec "${RXNS}" \
+				cat /sys/class/net/"$BOND_RX2_SLAVE_IF"/ifindex)
+
+	exec {TXNS_FD}</var/run/netns/"${TXNS}"
+	exec {RXNS_FD}</var/run/netns/"${RXNS}"
+
+	# Linking TX ifaces to the RX ones (on the other namespace)
+	echo "${TXNS_FD}:$BOND_TX1_SLAVE_IFIDX $RXNS_FD:$BOND_RX1_SLAVE_IFIDX"  \
+		> "$NSIM_DEV_SYS_LINK"
+	echo "${TXNS_FD}:$BOND_TX2_SLAVE_IFIDX $RXNS_FD:$BOND_RX2_SLAVE_IFIDX"  \
+		> "$NSIM_DEV_SYS_LINK"
+
+	exec {TXNS_FD}<&-
+	exec {RXNS_FD}<&-
+}
+
+function create_all_ifaces() {
+	# setup_ns function is coming from lib.sh
+	setup_ns TXNS RXNS
+	export NAMESPACE="${RXNS}"
+
+	# Create two interfaces for RX and two for TX
+	create_ifaces_bond
+	# Link netlink ifaces
+	link_ifaces_bond
+}
+
+# configure DSTIF and SRCIF IPs
+function configure_ifaces_ips() {
+	local IP_VERSION=${1:-"ipv4"}
+	select_ipv4_or_ipv6 "${IP_VERSION}"
+
+	ip -n "${RXNS}" addr add "${DSTIP}"/24 dev "${DSTIF}"
+	ip -n "${RXNS}" link set "${DSTIF}" up
+
+	ip -n "${TXNS}" addr add "${SRCIP}"/24 dev "${SRCIF}"
+	ip -n "${TXNS}" link set "${SRCIF}" up
+}
+
+function test_enable_netpoll_on_enslaved_iface() {
+	echo 0 > "${NETCONS_PATH}"/enabled
+
+	# At this stage, BOND_TX1_SLAVE_IF is enslaved to BOND_TX_MAIN_IF, and
+	# linked to BOND_RX1_SLAVE_IF inside the namespace.
+	echo "${BOND_TX1_SLAVE_IF}" > "${NETCONS_PATH}"/dev_name
+
+	# This should fail with the following message in dmesg:
+	# netpoll: netconsole: ethX is a slave device, aborting
+	set +e
+	enable_netcons_ns 2> /dev/null
+	set -e
+
+	if [[ $(cat "${NETCONS_PATH}"/enabled) -eq 1 ]]
+	then
+		echo "test failed: Bonding and netpoll cannot co-exists." >&2
+		exit "${ksft_fail}"
+	fi
+}
+
+function test_delete_bond_and_reenable_target() {
+	ip -n "${TXNS}" \
+		link delete "${BOND_TX_MAIN_IF}" type bond
+
+	# BOND_TX1_SLAVE_IF is not attached to a bond interface anymore
+	# netpoll can be plugged in there
+	echo "${BOND_TX1_SLAVE_IF}" > "${NETCONS_PATH}"/dev_name
+
+	# this should work, since the interface is not enslaved
+	enable_netcons_ns
+
+	if [[ $(cat "${NETCONS_PATH}"/enabled) -eq 0 ]]
+	then
+		echo "test failed: Unable to start netpoll on an unbond iface." >&2
+		exit "${ksft_fail}"
+	fi
+}
+
+# Send a netconsole message to the netconsole target
+function test_send_netcons_msg_through_bond_iface() {
+	# Listen for netconsole port inside the namespace and
+	# destination interface
+	listen_port_and_save_to "${OUTPUT_FILE}" "${IP_VERSION}" &
+	# Wait for socat to start and listen to the port.
+	wait_for_port "${RXNS}" "${PORT}" "${IP_VERSION}"
+	# Send the message
+	echo "${MSG}: ${TARGET}" > /dev/kmsg
+	# Wait until socat saves the file to disk
+	busywait "${BUSYWAIT_TIMEOUT}" test -s "${OUTPUT_FILE}"
+	# Make sure the message was received in the dst part
+	# and exit
+	validate_result "${OUTPUT_FILE}" "${FORMAT}"
+	# kill socat in case it is still running
+	pkill_socat
+}
+
+# BOND_TX1_SLAVE_IF has netconsole enabled on it, bind it to BOND_TX_MAIN_IF.
+# Given BOND_TX_MAIN_IF was deleted, recreate it first
+function test_enslave_netcons_enabled_iface {
+	# netconsole got disabled while the interface was down
+	if [[ $(cat "${NETCONS_PATH}"/enabled) -eq 0 ]]
+	then
+		echo "test failed: netconsole expected to be enabled against BOND_TX1_SLAVE_IF" >&2
+		exit "${ksft_fail}"
+	fi
+
+	# recreate the bonding iface. it got deleted by previous
+	# test (test_delete_bond_and_reenable_target)
+	ip -n "${TXNS}" \
+		link add "${BOND_TX_MAIN_IF}" type bond mode balance-rr
+
+	# sub-interface need to be down before attaching to bonding
+	# This will also disable netconsole.
+	ip -n "${TXNS}" \
+		link set "${BOND_TX1_SLAVE_IF}" down
+	ip -n "${TXNS}" \
+		link set "${BOND_TX1_SLAVE_IF}" master "${BOND_TX_MAIN_IF}"
+	ip -n "${TXNS}" \
+		link set "${BOND_TX_MAIN_IF}" up
+
+	# netconsole got disabled while the interface was down
+	if [[ $(cat "${NETCONS_PATH}"/enabled) -eq 1 ]]
+	then
+		echo "test failed: Device is part of a bond iface, cannot have netcons enabled" >&2
+		exit "${ksft_fail}"
+	fi
+}
+
+# Get netconsole enabled on a bonding interface and attach a second
+# sub-interface.
+function test_enslave_iface_to_bond {
+	# BOND_TX_MAIN_IF has only BOND_TX1_SLAVE_IF right now
+	echo "${BOND_TX_MAIN_IF}" > "${NETCONS_PATH}"/dev_name
+	enable_netcons_ns
+
+	# netcons is attached to bond0 and BOND_TX1_SLAVE_IF is
+	# part of BOND_TX_MAIN_IF. Attach BOND_TX2_SLAVE_IF to BOND_TX_MAIN_IF.
+	ip -n "${TXNS}" \
+		link set "${BOND_TX2_SLAVE_IF}" master "${BOND_TX_MAIN_IF}"
+	if [[ $(cat "${NETCONS_PATH}"/enabled) -eq 0 ]]
+	then
+		echo "test failed: Netconsole should be enabled on bonding interface. Failed" >&2
+		exit "${ksft_fail}"
+	fi
+}
+
+function test_enslave_iff_disabled_netpoll_iface {
+	local ret
+
+	# Create two interfaces. veth interfaces it known to have
+	# IFF_DISABLE_NETPOLL set
+	if ! ip link add "${VETH0}" type veth peer name "${VETH1}"
+	then
+		echo "Failed to create veth TX interface. Is CONFIG_VETH set?" >&2
+		exit "${ksft_skip}"
+	fi
+	set +e
+	# This will print RTNETLINK answers: Device or resource busy
+	ip link set "${VETH0}" master "${BOND_TX_MAIN_IF}" 2> /dev/null
+	ret=$?
+	set -e
+	if [[ $ret -eq 0 ]]
+	then
+		echo "test failed: veth interface could not be enslaved"
+		exit "${ksft_fail}"
+	fi
+}
+
+# Given that netconsole picks the current net namespace, we need to enable it
+# from inside the TXNS namespace
+function enable_netcons_ns() {
+	ip netns exec "${TXNS}" sh -c \
+		"mount -t configfs configfs /sys/kernel/config && echo 1 > $NETCONS_PATH/enabled"
+}
+
+####################
+# Tests start here #
+####################
+
+# Create regular interfaces using netdevsim and link them
+create_all_ifaces
+
+# Setup the bonding interfaces
+# BOND_RX_MAIN_IF has BOND_RX{1,2}_SLAVE_IF
+# BOND_TX_MAIN_IF has BOND_TX{1,2}_SLAVE_IF
+setup_bonding_ifaces
+
+# Configure the ips as BOND_RX1_SLAVE_IF and BOND_TX1_SLAVE_IF
+configure_ifaces_ips "${IP_VERSION}"
+
+_create_dynamic_target "${FORMAT}" "${NETCONS_PATH}"
+enable_netcons_ns
+set_user_data
+
+# Test #1 : Create an bonding interface and attach netpoll into
+# the bonding interface. Netconsole/netpoll should work on
+# the bonding interface.
+test_send_netcons_msg_through_bond_iface
+echo "test #1: netpoll on bonding interface worked. Test passed" >&2
+
+# Test #2: Attach netpoll to an enslaved interface
+# Try to attach netpoll to an enslaved sub-interface (while still being part of
+# a bonding interface), which shouldn't be allowed
+test_enable_netpoll_on_enslaved_iface
+echo "test #2: netpoll correctly rejected enslaved interface (expected behavior). Test passed." >&2
+
+# Test #3: Unplug the sub-interface from bond and enable netconsole
+# Detach the interface from a bonding interface and attach netpoll again
+test_delete_bond_and_reenable_target
+echo "test #3: Able to attach to an unbound interface. Test passed." >&2
+
+# Test #4: Enslave a sub-interface that had netconsole enabled
+# Try to enslave an interface that has netconsole/netpoll enabled.
+# Previous test has netconsole enabled in BOND_TX1_SLAVE_IF, try to enslave it
+test_enslave_netcons_enabled_iface
+echo "test #4: Enslaving an interface with netpoll attached. Test passed." >&2
+
+# Test #5: Enslave a sub-interface to a bonding interface
+# Enslave an interface to a bond interface that has netpoll attached
+# At this stage, BOND_TX_MAIN_IF is created and BOND_TX1_SLAVE_IF is part of
+# it. Netconsole is currently disabled
+test_enslave_iface_to_bond
+echo "test #5: Enslaving an interface to bond+netpoll. Test passed." >&2
+
+# Test #6: Enslave a IFF_DISABLE_NETPOLL sub-interface to a bonding interface
+# At this stage, BOND_TX_MAIN_IF has both sub interface and netconsole is
+# enabled. This test will try to enslave an a veth (IFF_DISABLE_NETPOLL) interface
+# and it should fail, with netpoll: veth0 doesn't support polling
+test_enslave_iff_disabled_netpoll_iface
+echo "test #6: Enslaving IFF_DISABLE_NETPOLL ifaces to bond iface is not supported. Test passed." >&2
+
+cleanup_bond
+trap - EXIT
+exit "${EXIT_STATUS}"

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

···
 LIBDIR=$(dirname "$(readlink -e "${BASH_SOURCE[0]}")")
 
 SRCIF="" # to be populated later
+SRCIP="" # to be populated later
 SRCIP4="192.0.2.1"
 SRCIP6="fc00::1"
 DSTIF="" # to be populated later
+DSTIP="" # to be populated later
 DSTIP4="192.0.2.2"
 DSTIP6="fc00::2"
 
···
 # NAMESPACE will be populated by setup_ns with a random value
 NAMESPACE=""
 
-# IDs for netdevsim
+# IDs for netdevsim. We either use NSIM_DEV_{1,2}_ID for standard test
+# or NSIM_BOND_{T,R}X_{1,2} for the bonding tests. Not both at the
+# same time.
 NSIM_DEV_1_ID=$((256 + RANDOM % 256))
 NSIM_DEV_2_ID=$((512 + RANDOM % 256))
+NSIM_BOND_TX_1=$((768 + RANDOM % 256))
+NSIM_BOND_TX_2=$((1024 + RANDOM % 256))
+NSIM_BOND_RX_1=$((1280 + RANDOM % 256))
+NSIM_BOND_RX_2=$((1536 + RANDOM % 256))
 NSIM_DEV_SYS_NEW="/sys/bus/netdevsim/new_device"
+NSIM_DEV_SYS_LINK="/sys/bus/netdevsim/link_device"
 
 # Used to create and delete namespaces
 source "${LIBDIR}"/../../../../net/lib.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
···
 	then
 		echo 1 > "${NCPATH}"/extended
 	fi
-
-	echo 1 > "${NCPATH}"/enabled
-
 }
 
 function create_dynamic_target() {
 	local FORMAT=${1:-"extended"}
 	local NCPATH=${2:-"$NETCONS_PATH"}
 	_create_dynamic_target "${FORMAT}" "${NCPATH}"
+
+	echo 1 > "${NCPATH}"/enabled
 
 	# This will make sure that the kernel was able to
 	# load the netconsole driver configuration. The console message
···
 	echo "${DEFAULT_PRINTK_VALUES}" > /proc/sys/kernel/printk
 }
 
-function cleanup() {
+function cleanup_netcons() {
 	# delete netconsole dynamic reconfiguration
-	echo 0 > "${NETCONS_PATH}"/enabled
+	# do not fail if the target is already disabled
+	if [[ ! -d "${NETCONS_PATH}" ]]
+	then
+		# in some cases this is called before netcons path is created
+		return
+	fi
+	if [[ $(cat "${NETCONS_PATH}"/enabled) != 0 ]]
+	then
+		echo 0 > "${NETCONS_PATH}"/enabled || true
+	fi
 	# Remove all the keys that got created during the selftest
 	find "${NETCONS_PATH}/userdata/" -mindepth 1 -type d -delete
 	# Remove the configfs entry
 	rmdir "${NETCONS_PATH}"
+}
 
+function cleanup() {
+	cleanup_netcons
 	do_cleanup
 }
 
···
 	# otherwise the packet could be missed, and the test will fail. Happens
 	# more frequently on IPv6
 	sleep 1
+}
+
+# Clean up netdevsim ifaces created for bonding test
+function cleanup_bond_nsim() {
+	ip -n "${TXNS}" \
+		link delete "${BOND_TX_MAIN_IF}" type bond || true
+	ip -n "${RXNS}" \
+		link delete "${BOND_RX_MAIN_IF}" type bond || true
+
+	cleanup_netdevsim "$NSIM_BOND_TX_1"
+	cleanup_netdevsim "$NSIM_BOND_TX_2"
+	cleanup_netdevsim "$NSIM_BOND_RX_1"
+	cleanup_netdevsim "$NSIM_BOND_RX_2"
+}
+
+# cleanup tests that use bonding interfaces
+function cleanup_bond() {
+	cleanup_netcons
+	cleanup_bond_nsim
+	cleanup_all_ns
+	ip link delete "${VETH0}" || true
 }