On 8/27/25 4:26 PM, Brett A C Sheffield wrote:
On 2025-08-27 08:23, 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
Link to discussion: https://lore.kernel.org/netdev/20250822165231.4353-4-bacs@librecast.net/
Thanks to Brett Sheffield for writing the initial version of this selftest!
Thanks for leaving my author name in the file. Perhaps you might consider adding:
Co-Authored-By: Brett A C Sheffield bacs@librecast.net
to your commit message. I spend quite a bit of my Saturday bisecting and diagnosing, and writing the patch and test.
I don't want to delay the fix, since I received other reports for the same problem, but I think proper recognition should be agreed by all the involved parties.
I'm going to apply patch 1/2 standalone, to allow repost for this one.
tools/testing/selftests/net/Makefile | 1 + .../selftests/net/broadcast_ether_dst.sh | 82 +++++++++++++++++++ 2 files changed, 83 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..865b5c7c8c8a --- /dev/null +++ b/tools/testing/selftests/net/broadcast_ether_dst.sh @@ -0,0 +1,82 @@ +#!/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 "${CAPFILE}"
- ip -net "${SERVER_NS}" link del link1
- cleanup_ns "${CLIENT_NS}" "${SERVER_NS}"
+}
+test_broadcast_ether_dst() {
- local rc=0
- CAPFILE=$(mktemp -u cap.XXXXXXXXXX)
- echo "Testing ethernet broadcast destination"
- # start tcpdump listening for icmp
- # tcpdump will exit after receiving a single packet
- # timeout will kill tcpdump if it is still running after 2s
- timeout 2s ip netns exec "${CLIENT_NS}" \
tcpdump -i link0 -c 1 -w "${CAPFILE}" icmp &> /dev/null &- pid=$!
- sleep 0.1 # let tcpdump wake up
Here you could use slowwait checking for packet socket creation, to be more robust WRT very slow env.
/P