[PATCH net v4] selftests: net: add test for destination in broadcast packets

[PATCH net v4] selftests: net: add test for destination in broadcast packets

[Oscar Maes]

Add test to check the broadcast ethernet destination field is set
correctly.

This test sends a broadcast ping, captures it using tcpdump and
ensures that all bits of the 6 octet ethernet destination address
are correctly set by examining the output capture file.

Signed-off-by: Oscar Maes <oscmaes92@gmail.com>
Co-authored-by: Brett A C Sheffield <bacs@librecast.net>
---
v3 -> v4:
 - Added Brett as co-author
 - Wait for tcpdump to bind using slowwait

Links:
 - Discussion: https://lore.kernel.org/netdev/20250822165231.4353-4-bacs@librecast.net/
 - Previous version: https://lore.kernel.org/netdev/20250827062322.4807-2-oscmaes92@gmail.com/

Thanks to Brett Sheffield for writing the initial version of this
selftest!

 tools/testing/selftests/net/Makefile          |  1 +
 .../selftests/net/broadcast_ether_dst.sh      | 83 +++++++++++++++++++
 2 files changed, 84 insertions(+)
 create mode 100755 tools/testing/selftests/net/broadcast_ether_dst.sh

diff --git a/tools/testing/selftests/net/Makefile b/tools/testing/selftests/net/Makefile
index b31a71f2b372..56ad10ea6628 100644
--- a/tools/testing/selftests/net/Makefile
+++ b/tools/testing/selftests/net/Makefile
@@ -115,6 +115,7 @@ TEST_PROGS += skf_net_off.sh
 TEST_GEN_FILES += skf_net_off
 TEST_GEN_FILES += tfo
 TEST_PROGS += tfo_passive.sh
+TEST_PROGS += broadcast_ether_dst.sh
 TEST_PROGS += broadcast_pmtu.sh
 TEST_PROGS += ipv6_force_forwarding.sh
 
diff --git a/tools/testing/selftests/net/broadcast_ether_dst.sh b/tools/testing/selftests/net/broadcast_ether_dst.sh
new file mode 100755
index 000000000000..334a7eca8a80
--- /dev/null
+++ b/tools/testing/selftests/net/broadcast_ether_dst.sh
@@ -0,0 +1,83 @@
+#!/bin/bash
+# SPDX-License-Identifier: GPL-2.0
+#
+# Author: Brett A C Sheffield <bacs@librecast.net>
+# Author: Oscar Maes <oscmaes92@gmail.com>
+#
+# Ensure destination ethernet field is correctly set for
+# broadcast packets
+
+source lib.sh
+
+CLIENT_IP4="192.168.0.1"
+GW_IP4="192.168.0.2"
+
+setup() {
+	setup_ns CLIENT_NS SERVER_NS
+
+	ip -net "${SERVER_NS}" link add link1 type veth \
+		peer name link0 netns "${CLIENT_NS}"
+
+	ip -net "${CLIENT_NS}" link set link0 up
+	ip -net "${CLIENT_NS}" addr add "${CLIENT_IP4}"/24 dev link0
+
+	ip -net "${SERVER_NS}" link set link1 up
+
+	ip -net "${CLIENT_NS}" route add default via "${GW_IP4}"
+	ip netns exec "${CLIENT_NS}" arp -s "${GW_IP4}" 00:11:22:33:44:55
+}
+
+cleanup() {
+	rm -f "${CAPFILE}" "${OUTPUT}"
+	ip -net "${SERVER_NS}" link del link1
+	cleanup_ns "${CLIENT_NS}" "${SERVER_NS}"
+}
+
+test_broadcast_ether_dst() {
+	local rc=0
+	CAPFILE=$(mktemp -u cap.XXXXXXXXXX)
+	OUTPUT=$(mktemp -u out.XXXXXXXXXX)
+
+	echo "Testing ethernet broadcast destination"
+
+	# start tcpdump listening for icmp
+	# tcpdump will exit after receiving a single packet
+	# timeout will kill tcpdump if it is still running after 2s
+	timeout 2s ip netns exec "${CLIENT_NS}" \
+		tcpdump -i link0 -c 1 -w "${CAPFILE}" icmp &> "${OUTPUT}" &
+	pid=$!
+	slowwait 1 grep -qs "listening" "${OUTPUT}"
+
+	# send broadcast ping
+	ip netns exec "${CLIENT_NS}" \
+		ping -W0.01 -c1 -b 255.255.255.255 &> /dev/null
+
+	# wait for tcpdump for exit after receiving packet
+	wait "${pid}"
+
+	# compare ethernet destination field to ff:ff:ff:ff:ff:ff
+	ether_dst=$(tcpdump -r "${CAPFILE}" -tnne 2>/dev/null | \
+			awk '{sub(/,/,"",$3); print $3}')
+	if [[ "${ether_dst}" == "ff:ff:ff:ff:ff:ff" ]]; then
+		echo "[ OK ]"
+		rc="${ksft_pass}"
+	else
+		echo "[FAIL] expected dst ether addr to be ff:ff:ff:ff:ff:ff," \
+			"got ${ether_dst}"
+		rc="${ksft_fail}"
+	fi
+
+	return "${rc}"
+}
+
+if [ ! -x "$(command -v tcpdump)" ]; then
+	echo "SKIP: Could not run test without tcpdump tool"
+	exit "${ksft_skip}"
+fi
+
+trap cleanup EXIT
+
+setup
+test_broadcast_ether_dst
+
+exit $?
-- 
2.39.5

Re: [PATCH net v4] selftests: net: add test for destination in broadcast packets

[Brett A C Sheffield]

On 2025-08-28 13:42, Oscar Maes wrote:
> Add test to check the broadcast ethernet destination field is set
> correctly.
> 
> This test sends a broadcast ping, captures it using tcpdump and
> ensures that all bits of the 6 octet ethernet destination address
> are correctly set by examining the output capture file.
> 
> Signed-off-by: Oscar Maes <oscmaes92@gmail.com>
> Co-authored-by: Brett A C Sheffield <bacs@librecast.net>
> ---
> v3 -> v4:
>  - Added Brett as co-author
>  - Wait for tcpdump to bind using slowwait

Thanks Oscar.

I've tested the v4 selftest on a kernel with the regression and one without and
it looks good.

6.17.0-rc3
Testing ethernet broadcast destination
[FAIL] expected dst ether addr to be ff:ff:ff:ff:ff:ff, got 00:11:22:33:44:55

6.17.0-rc3-00002-g329af5eb13d7 (with v3 patch applied)
Testing ethernet broadcast destination
[ OK ]

> Links:
>  - Discussion: https://lore.kernel.org/netdev/20250822165231.4353-4-bacs@librecast.net/
>  - Previous version: https://lore.kernel.org/netdev/20250827062322.4807-2-oscmaes92@gmail.com/
> 
> Thanks to Brett Sheffield for writing the initial version of this
> selftest!
> 
>  tools/testing/selftests/net/Makefile          |  1 +
>  .../selftests/net/broadcast_ether_dst.sh      | 83 +++++++++++++++++++
>  2 files changed, 84 insertions(+)
>  create mode 100755 tools/testing/selftests/net/broadcast_ether_dst.sh
> 
> diff --git a/tools/testing/selftests/net/Makefile b/tools/testing/selftests/net/Makefile
> index b31a71f2b372..56ad10ea6628 100644
> --- a/tools/testing/selftests/net/Makefile
> +++ b/tools/testing/selftests/net/Makefile
> @@ -115,6 +115,7 @@ TEST_PROGS += skf_net_off.sh
>  TEST_GEN_FILES += skf_net_off
>  TEST_GEN_FILES += tfo
>  TEST_PROGS += tfo_passive.sh
> +TEST_PROGS += broadcast_ether_dst.sh
>  TEST_PROGS += broadcast_pmtu.sh
>  TEST_PROGS += ipv6_force_forwarding.sh
>  
> diff --git a/tools/testing/selftests/net/broadcast_ether_dst.sh b/tools/testing/selftests/net/broadcast_ether_dst.sh
> new file mode 100755
> index 000000000000..334a7eca8a80
> --- /dev/null
> +++ b/tools/testing/selftests/net/broadcast_ether_dst.sh
> @@ -0,0 +1,83 @@
> +#!/bin/bash
> +# SPDX-License-Identifier: GPL-2.0
> +#
> +# Author: Brett A C Sheffield <bacs@librecast.net>
> +# Author: Oscar Maes <oscmaes92@gmail.com>
> +#
> +# Ensure destination ethernet field is correctly set for
> +# broadcast packets
> +
> +source lib.sh
> +
> +CLIENT_IP4="192.168.0.1"
> +GW_IP4="192.168.0.2"
> +
> +setup() {
> +	setup_ns CLIENT_NS SERVER_NS
> +
> +	ip -net "${SERVER_NS}" link add link1 type veth \
> +		peer name link0 netns "${CLIENT_NS}"
> +
> +	ip -net "${CLIENT_NS}" link set link0 up
> +	ip -net "${CLIENT_NS}" addr add "${CLIENT_IP4}"/24 dev link0
> +
> +	ip -net "${SERVER_NS}" link set link1 up
> +
> +	ip -net "${CLIENT_NS}" route add default via "${GW_IP4}"
> +	ip netns exec "${CLIENT_NS}" arp -s "${GW_IP4}" 00:11:22:33:44:55
> +}
> +
> +cleanup() {
> +	rm -f "${CAPFILE}" "${OUTPUT}"
> +	ip -net "${SERVER_NS}" link del link1
> +	cleanup_ns "${CLIENT_NS}" "${SERVER_NS}"
> +}
> +
> +test_broadcast_ether_dst() {
> +	local rc=0
> +	CAPFILE=$(mktemp -u cap.XXXXXXXXXX)
> +	OUTPUT=$(mktemp -u out.XXXXXXXXXX)
> +
> +	echo "Testing ethernet broadcast destination"
> +
> +	# start tcpdump listening for icmp
> +	# tcpdump will exit after receiving a single packet
> +	# timeout will kill tcpdump if it is still running after 2s
> +	timeout 2s ip netns exec "${CLIENT_NS}" \
> +		tcpdump -i link0 -c 1 -w "${CAPFILE}" icmp &> "${OUTPUT}" &
> +	pid=$!
> +	slowwait 1 grep -qs "listening" "${OUTPUT}"
> +
> +	# send broadcast ping
> +	ip netns exec "${CLIENT_NS}" \
> +		ping -W0.01 -c1 -b 255.255.255.255 &> /dev/null
> +
> +	# wait for tcpdump for exit after receiving packet
> +	wait "${pid}"
> +
> +	# compare ethernet destination field to ff:ff:ff:ff:ff:ff
> +	ether_dst=$(tcpdump -r "${CAPFILE}" -tnne 2>/dev/null | \
> +			awk '{sub(/,/,"",$3); print $3}')
> +	if [[ "${ether_dst}" == "ff:ff:ff:ff:ff:ff" ]]; then
> +		echo "[ OK ]"
> +		rc="${ksft_pass}"
> +	else
> +		echo "[FAIL] expected dst ether addr to be ff:ff:ff:ff:ff:ff," \
> +			"got ${ether_dst}"
> +		rc="${ksft_fail}"
> +	fi
> +
> +	return "${rc}"
> +}
> +
> +if [ ! -x "$(command -v tcpdump)" ]; then
> +	echo "SKIP: Could not run test without tcpdump tool"
> +	exit "${ksft_skip}"
> +fi
> +
> +trap cleanup EXIT
> +
> +setup
> +test_broadcast_ether_dst
> +
> +exit $?
> -- 
> 2.39.5
> 
> 

Re: [PATCH net v4] selftests: net: add test for destination in broadcast packets

[Simon Horman]

On Thu, Aug 28, 2025 at 01:42:42PM +0200, Oscar Maes wrote:
> Add test to check the broadcast ethernet destination field is set
> correctly.
> 
> This test sends a broadcast ping, captures it using tcpdump and
> ensures that all bits of the 6 octet ethernet destination address
> are correctly set by examining the output capture file.
> 
> Signed-off-by: Oscar Maes <oscmaes92@gmail.com>
> Co-authored-by: Brett A C Sheffield <bacs@librecast.net>

...

> +test_broadcast_ether_dst() {
> +	local rc=0
> +	CAPFILE=$(mktemp -u cap.XXXXXXXXXX)
> +	OUTPUT=$(mktemp -u out.XXXXXXXXXX)
> +
> +	echo "Testing ethernet broadcast destination"
> +
> +	# start tcpdump listening for icmp
> +	# tcpdump will exit after receiving a single packet
> +	# timeout will kill tcpdump if it is still running after 2s
> +	timeout 2s ip netns exec "${CLIENT_NS}" \
> +		tcpdump -i link0 -c 1 -w "${CAPFILE}" icmp &> "${OUTPUT}" &
> +	pid=$!
> +	slowwait 1 grep -qs "listening" "${OUTPUT}"
> +
> +	# send broadcast ping
> +	ip netns exec "${CLIENT_NS}" \
> +		ping -W0.01 -c1 -b 255.255.255.255 &> /dev/null
> +
> +	# wait for tcpdump for exit after receiving packet
> +	wait "${pid}"

Hi Oscar and Brett,

I am concerned that if something goes wrong this may block forever.
Also, I'm wondering if this test could make use of the tcpdump helpers
provided in tools/testing/selftests/net/forwarding/lib.sh

> +
> +	# compare ethernet destination field to ff:ff:ff:ff:ff:ff
> +	ether_dst=$(tcpdump -r "${CAPFILE}" -tnne 2>/dev/null | \
> +			awk '{sub(/,/,"",$3); print $3}')
> +	if [[ "${ether_dst}" == "ff:ff:ff:ff:ff:ff" ]]; then
> +		echo "[ OK ]"
> +		rc="${ksft_pass}"
> +	else
> +		echo "[FAIL] expected dst ether addr to be ff:ff:ff:ff:ff:ff," \
> +			"got ${ether_dst}"
> +		rc="${ksft_fail}"
> +	fi
> +
> +	return "${rc}"
> +}

...

Re: [PATCH net v4] selftests: net: add test for destination in broadcast packets

[Brett Sheffield]

On 2025-08-29 12:19, Simon Horman wrote:
> On Thu, Aug 28, 2025 at 01:42:42PM +0200, Oscar Maes wrote:
> > Add test to check the broadcast ethernet destination field is set
> > correctly.
> > 
> > This test sends a broadcast ping, captures it using tcpdump and
> > ensures that all bits of the 6 octet ethernet destination address
> > are correctly set by examining the output capture file.
> > 
> > Signed-off-by: Oscar Maes <oscmaes92@gmail.com>
> > Co-authored-by: Brett A C Sheffield <bacs@librecast.net>
> 
> ...
> 
> > +test_broadcast_ether_dst() {
> > +	local rc=0
> > +	CAPFILE=$(mktemp -u cap.XXXXXXXXXX)
> > +	OUTPUT=$(mktemp -u out.XXXXXXXXXX)
> > +
> > +	echo "Testing ethernet broadcast destination"
> > +
> > +	# start tcpdump listening for icmp
> > +	# tcpdump will exit after receiving a single packet
> > +	# timeout will kill tcpdump if it is still running after 2s
> > +	timeout 2s ip netns exec "${CLIENT_NS}" \
> > +		tcpdump -i link0 -c 1 -w "${CAPFILE}" icmp &> "${OUTPUT}" &
> > +	pid=$!
> > +	slowwait 1 grep -qs "listening" "${OUTPUT}"
> > +
> > +	# send broadcast ping
> > +	ip netns exec "${CLIENT_NS}" \
> > +		ping -W0.01 -c1 -b 255.255.255.255 &> /dev/null
> > +
> > +	# wait for tcpdump for exit after receiving packet
> > +	wait "${pid}"
> 
> Hi Oscar and Brett,
> 
> I am concerned that if something goes wrong this may block forever.
> Also, I'm wondering if this test could make use of the tcpdump helpers
> provided in tools/testing/selftests/net/forwarding/lib.sh

tcpdump is started with `timeout 2s`, which will kill it if the 2s timeout is
exceeded.  Is that not sufficient here?

> > +
> > +	# compare ethernet destination field to ff:ff:ff:ff:ff:ff
> > +	ether_dst=$(tcpdump -r "${CAPFILE}" -tnne 2>/dev/null | \
> > +			awk '{sub(/,/,"",$3); print $3}')
> > +	if [[ "${ether_dst}" == "ff:ff:ff:ff:ff:ff" ]]; then
> > +		echo "[ OK ]"
> > +		rc="${ksft_pass}"
> > +	else
> > +		echo "[FAIL] expected dst ether addr to be ff:ff:ff:ff:ff:ff," \
> > +			"got ${ether_dst}"
> > +		rc="${ksft_fail}"
> > +	fi
> > +
> > +	return "${rc}"
> > +}
> 
> ...

bacs
-- 

Re: [PATCH net v4] selftests: net: add test for destination in broadcast packets

[Brett Sheffield]

On 2025-08-29 12:19, Simon Horman wrote:
> On Thu, Aug 28, 2025 at 01:42:42PM +0200, Oscar Maes wrote:
> > Add test to check the broadcast ethernet destination field is set
> > correctly.
> > 
> > This test sends a broadcast ping, captures it using tcpdump and
> > ensures that all bits of the 6 octet ethernet destination address
> > are correctly set by examining the output capture file.
> > 
> > Signed-off-by: Oscar Maes <oscmaes92@gmail.com>
> > Co-authored-by: Brett A C Sheffield <bacs@librecast.net>
> 
> ...
> 
> > +test_broadcast_ether_dst() {
> > +	local rc=0
> > +	CAPFILE=$(mktemp -u cap.XXXXXXXXXX)
> > +	OUTPUT=$(mktemp -u out.XXXXXXXXXX)
> > +
> > +	echo "Testing ethernet broadcast destination"
> > +
> > +	# start tcpdump listening for icmp
> > +	# tcpdump will exit after receiving a single packet
> > +	# timeout will kill tcpdump if it is still running after 2s
> > +	timeout 2s ip netns exec "${CLIENT_NS}" \
> > +		tcpdump -i link0 -c 1 -w "${CAPFILE}" icmp &> "${OUTPUT}" &
> > +	pid=$!
> > +	slowwait 1 grep -qs "listening" "${OUTPUT}"
> > +
> > +	# send broadcast ping
> > +	ip netns exec "${CLIENT_NS}" \
> > +		ping -W0.01 -c1 -b 255.255.255.255 &> /dev/null
> > +
> > +	# wait for tcpdump for exit after receiving packet
> > +	wait "${pid}"
> 
> Hi Oscar and Brett,
> 
> I am concerned that if something goes wrong this may block forever.
> Also, I'm wondering if this test could make use of the tcpdump helpers
> provided in tools/testing/selftests/net/forwarding/lib.sh

Thanks for the review Simon.  Further to previous email after some more thought
and poking at lib.sh

We're starting tcpdump with -c1 so that it exits immediately when the packet is
received, and we catch this with the wait() so that, in the best case, we
continue immediately, and in the worse case the `timeout 2s` kills tcpdump and
we move on to cleanup. I *think* this is pretty safe.

Taking a look at the forwarding/lib.sh it looks like we could use
tcpdump_start() and pass in $TCPDUMP_EXTRA_FLAGS but I don't think this buys us
much here, as we'd still need to wait() or a sleep() or otherwise detect that
tcpdump is finished so we can continue. I don't see anything in lib.sh to aid us
with that?

That said, it might be good to use the helper function anyway and keep the
wait() for consistency. There don't seem to be many tests using the tcpdump
helper functions yet, but it's probably the right way to move.

What do you think, Oscar?  It looks like lib.sh tcpdump_start() takes all the
arguments, including for your namespaces.  Up to you if you want to call that
instead.

Now I know it's there, I'll try to use that for future tests.

I don't *think* there's anything here that needs a v4, unless the timeout() call
is thought to be insufficient to kill tcpdump.  There's a -k switch if we want
to SIGKILL it :-)

> > +
> > +	# compare ethernet destination field to ff:ff:ff:ff:ff:ff
> > +	ether_dst=$(tcpdump -r "${CAPFILE}" -tnne 2>/dev/null | \
> > +			awk '{sub(/,/,"",$3); print $3}')
> > +	if [[ "${ether_dst}" == "ff:ff:ff:ff:ff:ff" ]]; then
> > +		echo "[ OK ]"
> > +		rc="${ksft_pass}"
> > +	else
> > +		echo "[FAIL] expected dst ether addr to be ff:ff:ff:ff:ff:ff," \
> > +			"got ${ether_dst}"
> > +		rc="${ksft_fail}"
> > +	fi
> > +
> > +	return "${rc}"
> > +}
> 
> ...

-- 
Brett Sheffield (he/him)
Librecast - Decentralising the Internet with Multicast
https://librecast.net/
https://blog.brettsheffield.com/

Re: [PATCH net v4] selftests: net: add test for destination in broadcast packets

[Oscar Maes]

On Fri, Aug 29, 2025 at 03:11:20PM +0200, Brett Sheffield wrote:
> On 2025-08-29 12:19, Simon Horman wrote:
> > On Thu, Aug 28, 2025 at 01:42:42PM +0200, Oscar Maes wrote:
> > > Add test to check the broadcast ethernet destination field is set
> > > correctly.
> > > 
> > > This test sends a broadcast ping, captures it using tcpdump and
> > > ensures that all bits of the 6 octet ethernet destination address
> > > are correctly set by examining the output capture file.
> > > 
> > > Signed-off-by: Oscar Maes <oscmaes92@gmail.com>
> > > Co-authored-by: Brett A C Sheffield <bacs@librecast.net>
> > 
> > ...
> > 
> > > +test_broadcast_ether_dst() {
> > > +	local rc=0
> > > +	CAPFILE=$(mktemp -u cap.XXXXXXXXXX)
> > > +	OUTPUT=$(mktemp -u out.XXXXXXXXXX)
> > > +
> > > +	echo "Testing ethernet broadcast destination"
> > > +
> > > +	# start tcpdump listening for icmp
> > > +	# tcpdump will exit after receiving a single packet
> > > +	# timeout will kill tcpdump if it is still running after 2s
> > > +	timeout 2s ip netns exec "${CLIENT_NS}" \
> > > +		tcpdump -i link0 -c 1 -w "${CAPFILE}" icmp &> "${OUTPUT}" &
> > > +	pid=$!
> > > +	slowwait 1 grep -qs "listening" "${OUTPUT}"
> > > +
> > > +	# send broadcast ping
> > > +	ip netns exec "${CLIENT_NS}" \
> > > +		ping -W0.01 -c1 -b 255.255.255.255 &> /dev/null
> > > +
> > > +	# wait for tcpdump for exit after receiving packet
> > > +	wait "${pid}"
> > 
> > Hi Oscar and Brett,
> > 
> > I am concerned that if something goes wrong this may block forever.
> > Also, I'm wondering if this test could make use of the tcpdump helpers
> > provided in tools/testing/selftests/net/forwarding/lib.sh
> 
> Thanks for the review Simon.  Further to previous email after some more thought
> and poking at lib.sh
> 
> We're starting tcpdump with -c1 so that it exits immediately when the packet is
> received, and we catch this with the wait() so that, in the best case, we
> continue immediately, and in the worse case the `timeout 2s` kills tcpdump and
> we move on to cleanup. I *think* this is pretty safe.
> 
> Taking a look at the forwarding/lib.sh it looks like we could use
> tcpdump_start() and pass in $TCPDUMP_EXTRA_FLAGS but I don't think this buys us
> much here, as we'd still need to wait() or a sleep() or otherwise detect that
> tcpdump is finished so we can continue. I don't see anything in lib.sh to aid us
> with that?
> 
> That said, it might be good to use the helper function anyway and keep the
> wait() for consistency. There don't seem to be many tests using the tcpdump
> helper functions yet, but it's probably the right way to move.
> 
> What do you think, Oscar?  It looks like lib.sh tcpdump_start() takes all the
> arguments, including for your namespaces.  Up to you if you want to call that
> instead.
> 
> Now I know it's there, I'll try to use that for future tests.
> 
> I don't *think* there's anything here that needs a v4, unless the timeout() call
> is thought to be insufficient to kill tcpdump.  There's a -k switch if we want
> to SIGKILL it :-)
> 

I agree with Brett here.
I tried using forwarding/lib.sh but it made the test unnecessarily complex
and difficult to read/debug. I suggest we keep it as-is.

Simon - what do you think?

> > > +
> > > +	# compare ethernet destination field to ff:ff:ff:ff:ff:ff
> > > +	ether_dst=$(tcpdump -r "${CAPFILE}" -tnne 2>/dev/null | \
> > > +			awk '{sub(/,/,"",$3); print $3}')
> > > +	if [[ "${ether_dst}" == "ff:ff:ff:ff:ff:ff" ]]; then
> > > +		echo "[ OK ]"
> > > +		rc="${ksft_pass}"
> > > +	else
> > > +		echo "[FAIL] expected dst ether addr to be ff:ff:ff:ff:ff:ff," \
> > > +			"got ${ether_dst}"
> > > +		rc="${ksft_fail}"
> > > +	fi
> > > +
> > > +	return "${rc}"
> > > +}
> > 
> > ...
> 
> -- 
> Brett Sheffield (he/him)
> Librecast - Decentralising the Internet with Multicast
> https://librecast.net/
> https://blog.brettsheffield.com/

Re: [PATCH net v4] selftests: net: add test for destination in broadcast packets

[Paolo Abeni]

On 8/28/25 1:42 PM, Oscar Maes wrote:
> Add test to check the broadcast ethernet destination field is set
> correctly.
> 
> This test sends a broadcast ping, captures it using tcpdump and
> ensures that all bits of the 6 octet ethernet destination address
> are correctly set by examining the output capture file.
> 
> Signed-off-by: Oscar Maes <oscmaes92@gmail.com>
> Co-authored-by: Brett A C Sheffield <bacs@librecast.net>

I'm sorry for nit-picking, but the sob/tag-chain is wrong, please have a
look at:

https://elixir.bootlin.com/linux/v6.16.4/source/Documentation/process/submitting-patches.rst#L516

Thanks,

Paolo

Re: [PATCH net v4] selftests: net: add test for destination in broadcast packets

[Brett Sheffield]

On 2025-09-02 10:49, Paolo Abeni wrote:
> On 8/28/25 1:42 PM, Oscar Maes wrote:
> > Add test to check the broadcast ethernet destination field is set
> > correctly.
> > 
> > This test sends a broadcast ping, captures it using tcpdump and
> > ensures that all bits of the 6 octet ethernet destination address
> > are correctly set by examining the output capture file.
> > 
> > Signed-off-by: Oscar Maes <oscmaes92@gmail.com>
> > Co-authored-by: Brett A C Sheffield <bacs@librecast.net>
> 
> I'm sorry for nit-picking, but the sob/tag-chain is wrong, please have a
> look at:
> 
> https://elixir.bootlin.com/linux/v6.16.4/source/Documentation/process/submitting-patches.rst#L516

Thanks Paolo. So, something like:

Co-developed-by: Brett A C Sheffield <bacs@librecast.net>
Signed-off-by: Brett A C Sheffield <bacs@librecast.net>
Co-developed-by: Oscar Maes <oscmaes92@gmail.com>
Signed-off-by: Oscar Maes <oscmaes92@gmail.com>

with the last sign-off by Oscar because he is submitting?


Brett

Re: [PATCH net v4] selftests: net: add test for destination in broadcast packets

[Paolo Abeni]

On 9/2/25 11:33 AM, Brett Sheffield wrote:
> On 2025-09-02 10:49, Paolo Abeni wrote:
>> On 8/28/25 1:42 PM, Oscar Maes wrote:
>>> Add test to check the broadcast ethernet destination field is set
>>> correctly.
>>>
>>> This test sends a broadcast ping, captures it using tcpdump and
>>> ensures that all bits of the 6 octet ethernet destination address
>>> are correctly set by examining the output capture file.
>>>
>>> Signed-off-by: Oscar Maes <oscmaes92@gmail.com>
>>> Co-authored-by: Brett A C Sheffield <bacs@librecast.net>
>>
>> I'm sorry for nit-picking, but the sob/tag-chain is wrong, please have a
>> look at:
>>
>> https://elixir.bootlin.com/linux/v6.16.4/source/Documentation/process/submitting-patches.rst#L516
> 
> Thanks Paolo. So, something like:
> 
> Co-developed-by: Brett A C Sheffield <bacs@librecast.net>
> Signed-off-by: Brett A C Sheffield <bacs@librecast.net>
> Co-developed-by: Oscar Maes <oscmaes92@gmail.com>
> Signed-off-by: Oscar Maes <oscmaes92@gmail.com>
> 
> with the last sign-off by Oscar because he is submitting?

Actually my understanding is:

Co-developed-by: Brett A C Sheffield <bacs@librecast.net>
Signed-off-by: Brett A C Sheffield <bacs@librecast.net>
Signed-off-by: Oscar Maes <oscmaes92@gmail.com>

(if the patch is submitted by Oscar.) Basically the first examples in
the doc, with the only differences that such examples lists 3 co-developers.

/P

Re: [PATCH net v4] selftests: net: add test for destination in broadcast packets

[Brett Sheffield]

On 2025-09-02 11:57, Paolo Abeni wrote:
> 
> 
> On 9/2/25 11:33 AM, Brett Sheffield wrote:
> > On 2025-09-02 10:49, Paolo Abeni wrote:
> >> On 8/28/25 1:42 PM, Oscar Maes wrote:
> >>> Add test to check the broadcast ethernet destination field is set
> >>> correctly.
> >>>
> >>> This test sends a broadcast ping, captures it using tcpdump and
> >>> ensures that all bits of the 6 octet ethernet destination address
> >>> are correctly set by examining the output capture file.
> >>>
> >>> Signed-off-by: Oscar Maes <oscmaes92@gmail.com>
> >>> Co-authored-by: Brett A C Sheffield <bacs@librecast.net>
> >>
> >> I'm sorry for nit-picking, but the sob/tag-chain is wrong, please have a
> >> look at:
> >>
> >> https://elixir.bootlin.com/linux/v6.16.4/source/Documentation/process/submitting-patches.rst#L516
> > 
> > Thanks Paolo. So, something like:
> > 
> > Co-developed-by: Brett A C Sheffield <bacs@librecast.net>
> > Signed-off-by: Brett A C Sheffield <bacs@librecast.net>
> > Co-developed-by: Oscar Maes <oscmaes92@gmail.com>
> > Signed-off-by: Oscar Maes <oscmaes92@gmail.com>
> > 
> > with the last sign-off by Oscar because he is submitting?
> 
> Actually my understanding is:
> 
> Co-developed-by: Brett A C Sheffield <bacs@librecast.net>
> Signed-off-by: Brett A C Sheffield <bacs@librecast.net>
> Signed-off-by: Oscar Maes <oscmaes92@gmail.com>
> 
> (if the patch is submitted by Oscar.) Basically the first examples in
> the doc, with the only differences that such examples lists 3 co-developers.

Ah yes, you are correct. I missed the "in addition to the author attributed by
the From: tag" bit.

Thanks again.


Brett