[PATCH net-next v3] net: netconsole: selftests: Create a new netconsole selftest

[PATCH net-next v3] net: netconsole: selftests: Create a new netconsole selftest

[Breno Leitao]

Adds a selftest that creates two virtual interfaces, assigns one to a
new namespace, and assigns IP addresses to both.

It listens on the destination interface using socat and configures a
dynamic target on netconsole, pointing to the destination IP address.

The test then checks if the message was received properly on the
destination interface.

Signed-off-by: Breno Leitao <leitao@debian.org>
---
Changelog:

v3:
 * Defined CONFIGs in config file (Jakub)
 * Identention fixes (Petr Machata)
 * Use setup_ns in a better way (Matthieu Baerts)
 * Add dependencies in TEST_INCLUDES (Hangbin Liu)

v2:
 * Change the location of the path (Jakub)
 * Move from veth to netdevsim
 * Other small changes in dependency checks and cleanup
 * https://lore.kernel.org/all/20240813183825.837091-1-leitao@debian.org/

v1:
 * https://lore.kernel.org/all/ZqyUHN770pjSofTC@gmail.com/

 MAINTAINERS                                   |   1 +
 tools/testing/selftests/drivers/net/Makefile  |   4 +-
 tools/testing/selftests/drivers/net/config    |   2 +
 .../selftests/drivers/net/netcons_basic.sh    | 226 ++++++++++++++++++
 4 files changed, 232 insertions(+), 1 deletion(-)
 create mode 100755 tools/testing/selftests/drivers/net/netcons_basic.sh

diff --git a/MAINTAINERS b/MAINTAINERS
index 7b291c3a9aa4..9f0be36939f9 100644
--- a/MAINTAINERS
+++ b/MAINTAINERS
@@ -15772,6 +15772,7 @@ M:	Breno Leitao <leitao@debian.org>
 S:	Maintained
 F:	Documentation/networking/netconsole.rst
 F:	drivers/net/netconsole.c
+F:	tools/testing/selftests/drivers/net/netcons_basic.sh
 
 NETDEVSIM
 M:	Jakub Kicinski <kuba@kernel.org>
diff --git a/tools/testing/selftests/drivers/net/Makefile b/tools/testing/selftests/drivers/net/Makefile
index e54f382bcb02..8bee2e94049b 100644
--- a/tools/testing/selftests/drivers/net/Makefile
+++ b/tools/testing/selftests/drivers/net/Makefile
@@ -1,8 +1,10 @@
 # SPDX-License-Identifier: GPL-2.0
 
-TEST_INCLUDES := $(wildcard lib/py/*.py)
+TEST_INCLUDES := $(wildcard lib/py/*.py) \
+		 ../../net/lib.sh \
 
 TEST_PROGS := \
+	netcons_basic.sh \
 	ping.py \
 	queues.py \
 	stats.py \
diff --git a/tools/testing/selftests/drivers/net/config b/tools/testing/selftests/drivers/net/config
index f6a58ce8a230..8f46112263f0 100644
--- a/tools/testing/selftests/drivers/net/config
+++ b/tools/testing/selftests/drivers/net/config
@@ -1,2 +1,4 @@
 CONFIG_IPV6=y
 CONFIG_NETDEVSIM=m
+CONFIG_NETCONSOLE=m
+CONFIG_NETCONSOLE_DYNAMIC=y
diff --git a/tools/testing/selftests/drivers/net/netcons_basic.sh b/tools/testing/selftests/drivers/net/netcons_basic.sh
new file mode 100755
index 000000000000..929f27a0fd9c
--- /dev/null
+++ b/tools/testing/selftests/drivers/net/netcons_basic.sh
@@ -0,0 +1,226 @@
+#!/usr/bin/env bash
+# SPDX-License-Identifier: GPL-2.0
+
+# This test creates two netdevsim virtual interfaces, assigns one of them (the
+# "destination interface") to a new namespace, and assigns IP addresses to both
+# interfaces.
+#
+# It listens on the destination interface using socat and configures a dynamic
+# target on netconsole, pointing to the destination IP address.
+#
+# Finally, it checks whether the message was received properly on the
+# destination interface.  Note that this test may pollute the kernel log buffer
+# (dmesg) and relies on dynamic configuration and namespaces being configured.
+#
+# Author: Breno Leitao <leitao@debian.org>
+
+set -euo pipefail
+
+SCRIPTDIR=$(dirname "$(readlink -e "${BASH_SOURCE[0]}")")
+
+# Simple script to test dynamic targets in netconsole
+SRCIF="" # to be populated later
+SRCIP=192.168.1.1
+DSTIF="" # to be populated later
+DSTIP=192.168.1.2
+
+PORT="6666"
+MSG="netconsole selftest"
+TARGET=$(mktemp -u netcons_XXXXX)
+NETCONS_CONFIGFS="/sys/kernel/config/netconsole"
+NETCONS_PATH="${NETCONS_CONFIGFS}"/"${TARGET}"
+# This will have some tmp values appended to it in set_network()
+NAMESPACE="netconsns_dst"
+
+# IDs for netdevsim
+NSIM_DEV_1_ID=$((256 + RANDOM % 256))
+NSIM_DEV_2_ID=$((512 + RANDOM % 256))
+
+# Used to create and delete namespaces
+source "${SCRIPTDIR}"/../../net/lib.sh
+
+# Create netdevsim interfaces
+create_ifaces() {
+	local NSIM_DEV_SYS_NEW=/sys/bus/netdevsim/new_device
+
+	echo "$NSIM_DEV_2_ID" > "$NSIM_DEV_SYS_NEW"
+	echo "$NSIM_DEV_1_ID" > "$NSIM_DEV_SYS_NEW"
+	udevadm settle || true
+
+	local NSIM1=/sys/bus/netdevsim/devices/netdevsim"$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}
+	echo "${INITNS_FD}:$SRCIF_IFIDX $NAMESPACE_FD:$DSTIF_IFIDX" \
+		> $NSIM_DEV_SYS_LINK
+	if [ $? -ne 0 ]; 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 "${SRCIF}" up
+}
+
+function set_network() {
+	# This is coming from lib.sh
+	setup_ns NAMESPACE
+
+	# Create both interfaces, and assign the destination to a different
+	# namespace
+	create_ifaces
+
+	# Link both interfaces back to back
+	link_ifaces
+
+	configure_ip
+}
+
+function create_dynamic_target() {
+	DSTMAC=$(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 the configfs entry
+	rmdir "${NETCONS_PATH}"
+
+	# Delete netdevsim devices
+	echo "$NSIM_DEV_2_ID" > "$NSIM_DEV_SYS_DEL"
+	echo "$NSIM_DEV_1_ID" > "$NSIM_DEV_SYS_DEL"
+
+	# this is coming from lib.sh
+	cleanup_all_ns
+}
+
+function listen_port_and_save_to() {
+	local OUTPUT=${1}
+	# Just wait for 2 seconds
+	timeout 2 ip netns exec "${NAMESPACE}" \
+		socat UDP-LISTEN:"${PORT}",fork "${OUTPUT}"
+}
+
+function validate_result() {
+	local TMPFILENAME="$1"
+
+	# Check if the file exists
+	if [ ! -f "$TMPFILENAME" ]; then
+		echo "FAIL: File was not generated." >&2
+		return ${ksft_fail}
+	fi
+
+	if ! grep -q "${MSG}" "${TMPFILENAME}"; then
+		echo "FAIL: ${MSG} not found in ${TMPFILENAME}" >&2
+		cat "${TMPFILENAME}" >&2
+	return ${ksft_fail}
+	fi
+
+	# Delete the file once it is validated, otherwise keep it
+	# for debugging purposes
+	rm "${TMPFILENAME}"
+	return ${ksft_pass}
+}
+
+function check_for_dependencies() {
+	if [ "$(id -u)" -ne 0 ]; then
+		echo "This script 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 [ ! -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
+}
+
+# ========== #
+# Start here #
+# ========== #
+modprobe netdevsim || true
+modprobe netconsole || true
+
+# The content of kmsg will be save to the following file
+OUTPUT_FILE="/tmp/${TARGET}"
+
+# Check for basic system dependency and exit if not found
+check_for_dependencies
+# Remove the namespace, interfaces and netconsole target on exit
+trap cleanup EXIT
+# Create one namespace and two interfaces
+set_network
+# Create a dynamic target for netconsole
+create_dynamic_target
+# Listed for netconsole port inside the namespace and destination interface
+listen_port_and_save_to "${OUTPUT_FILE}" &
+
+# Wait for socat to start and listen to the port.
+sleep 1
+# Send the message
+echo "${MSG}: ${TARGET}" > /dev/kmsg
+# Wait until socat saves the file to disk
+sleep 1
+
+# Make sure the message was received in the dst part
+validate_result "${OUTPUT_FILE}"
+ret=$?
+
+exit ${ret}
-- 
2.43.5

Re: [PATCH net-next v3] net: netconsole: selftests: Create a new netconsole selftest

[Matthieu Baerts]

Hi Breno,

On 15/08/2024 11:51, Breno Leitao wrote:
> Adds a selftest that creates two virtual interfaces, assigns one to a
> new namespace, and assigns IP addresses to both.
> 
> It listens on the destination interface using socat and configures a
> dynamic target on netconsole, pointing to the destination IP address.
> 
> The test then checks if the message was received properly on the
> destination interface.
> 
> Signed-off-by: Breno Leitao <leitao@debian.org>
> ---
> Changelog:
> 
> v3:
>  * Defined CONFIGs in config file (Jakub)
>  * Identention fixes (Petr Machata)
>  * Use setup_ns in a better way (Matthieu Baerts)
>  * Add dependencies in TEST_INCLUDES (Hangbin Liu)

Thank you for the v3!

I only looked here at how 'setup_ns' was used, (and a few other
Bash-related stuff), but not at the test itself.

I have a few comments, but I don't consider them as blocking if you
prefer to continue with the current version.

(...)

> diff --git a/tools/testing/selftests/drivers/net/netcons_basic.sh b/tools/testing/selftests/drivers/net/netcons_basic.sh
> new file mode 100755
> index 000000000000..929f27a0fd9c
> --- /dev/null
> +++ b/tools/testing/selftests/drivers/net/netcons_basic.sh
> @@ -0,0 +1,226 @@

(...)

> +# This will have some tmp values appended to it in set_network()
> +NAMESPACE="netconsns_dst"

nit: the comment is no longer correct: if this variable is set before
being used with setup_ns, the netns will not have a unique name, but it
will use the one defined here. Maybe not what you want?

See this code from lib.sh where "ns_name" is "NAMESPACE":

  # Some test may setup/remove same netns multi times
  if [ -z "${!ns_name}" ]; then
          eval "${ns_name}=${ns_name,,}-$(mktemp -u XXXXXX)"
  else
          cleanup_ns "${!ns_name}"
  fi

So it will not set a new value, but it will try to clean any netns with
this "netconsns_dst" name. I guess that's fine, but maybe you prefer to
do like the others and simply define "NAMESPACE" to an empty string?

(...)

> +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 "${NAMESPACE}"
> +
> +	# Linking one device to the other one (on the other namespace}
> +	echo "${INITNS_FD}:$SRCIF_IFIDX $NAMESPACE_FD:$DSTIF_IFIDX" \
> +		> $NSIM_DEV_SYS_LINK
> +	if [ $? -ne 0 ]; then

Because of the 'set -e' defined above, I guess the script will stop just
before in case of error, no? Maybe better with:

  if ! echo "(...)" > $NSIM_DEV_SYS_LINK; then

(note that shellcheck should help to spot such issues I think)

> +		echo "linking netdevsim1 with netdevsim2 should succeed"
> +		cleanup
> +		exit ${ksft_skip}
> +	fi
> +}

(...)

> +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="$1"
> +
> +	# Check if the file exists
> +	if [ ! -f "$TMPFILENAME" ]; then
> +		echo "FAIL: File was not generated." >&2
> +		return ${ksft_fail}
> +	fi
> +
> +	if ! grep -q "${MSG}" "${TMPFILENAME}"; then
> +		echo "FAIL: ${MSG} not found in ${TMPFILENAME}" >&2
> +		cat "${TMPFILENAME}" >&2
> +	return ${ksft_fail}

nit: a tab is missing here.

> +	fi
> +
> +	# Delete the file once it is validated, otherwise keep it
> +	# for debugging purposes
> +	rm "${TMPFILENAME}"
> +	return ${ksft_pass}
> +}

(...)

> +# ========== #
> +# Start here #
> +# ========== #
> +modprobe netdevsim || true
> +modprobe netconsole || true

If errors can be expected, maybe clearer to mute stderr, not to confuse
the people reading the logs?

Same above with 'udevadm settle || true'.

> +
> +# The content of kmsg will be save to the following file
> +OUTPUT_FILE="/tmp/${TARGET}"
> +
> +# Check for basic system dependency and exit if not found
> +check_for_dependencies
> +# Remove the namespace, interfaces and netconsole target on exit
> +trap cleanup EXIT
> +# Create one namespace and two interfaces
> +set_network
> +# Create a dynamic target for netconsole
> +create_dynamic_target
> +# Listed for netconsole port inside the namespace and destination interface
> +listen_port_and_save_to "${OUTPUT_FILE}" &
> +
> +# Wait for socat to start and listen to the port.
> +sleep 1

I guess that's fine as it is, but it is often better to avoid a sleep
with a "random" value: CI can be very slow, e.g. when running without
KVM and/or with a debug kernel config. Here, wait_local_port_listen()
from net_helper.sh could probably be used. The script will then probably
wait less than 1 second.

> +# Send the message
> +echo "${MSG}: ${TARGET}" > /dev/kmsg
> +# Wait until socat saves the file to disk
> +sleep 1

For here, I'm not sure, but 'busywait()' could be used, waiting for the
OUTPUT_FILE to have a non 0 size?

If you do that, you can maybe increase the timeout you used above, to
support very slow environments.

But if you prefer, I guess you can also leave things like they are and
see if CIs are complaining (but these errors might not be easy to debug).

> +
> +# Make sure the message was received in the dst part
> +validate_result "${OUTPUT_FILE}"
> +ret=$?

Here as well, because of 'set -e', this line is probably useless.

  validate_result "${OUTPUT_FILE}" || ret=$?

(or exit directly from validate_result() )

> +
> +exit ${ret}

Cheers,
Matt
-- 
Sponsored by the NGI0 Core fund.

Re: [PATCH net-next v3] net: netconsole: selftests: Create a new netconsole selftest

[Jakub Kicinski]

On Thu, 15 Aug 2024 02:51:44 -0700 Breno Leitao wrote:
> +CONFIG_NETCONSOLE=m
> +CONFIG_NETCONSOLE_DYNAMIC=y

It's missing dependencies, configfs but maybe more.
Please test the build as described here:
https://github.com/linux-netdev/nipa/wiki/How-to-run-netdev-selftests-CI-style#how-to-build

Re: [PATCH net-next v3] net: netconsole: selftests: Create a new netconsole selftest

[Breno Leitao]

Hello Matthieu,

On Thu, Aug 15, 2024 at 12:47:22PM +0200, Matthieu Baerts wrote:
> On 15/08/2024 11:51, Breno Leitao wrote:
> > Adds a selftest that creates two virtual interfaces, assigns one to a
> > new namespace, and assigns IP addresses to both.
> > 
> > It listens on the destination interface using socat and configures a
> > dynamic target on netconsole, pointing to the destination IP address.
> > 
> > The test then checks if the message was received properly on the
> > destination interface.
> > 
> > Signed-off-by: Breno Leitao <leitao@debian.org>
> > ---
> > Changelog:
> > 
> > v3:
> >  * Defined CONFIGs in config file (Jakub)
> >  * Identention fixes (Petr Machata)
> >  * Use setup_ns in a better way (Matthieu Baerts)
> >  * Add dependencies in TEST_INCLUDES (Hangbin Liu)
> 
> Thank you for the v3!
> 
> I only looked here at how 'setup_ns' was used, (and a few other
> Bash-related stuff), but not at the test itself.
> 
> I have a few comments, but I don't consider them as blocking if you
> prefer to continue with the current version.

Thanks. I've adjusted all the suggestions you gave me, let me send a v4
and we can continue from there.

Thanks for the in-depth review.
--breno