mirrors/linux
2
0
Fork 0
mirror of https://git.kernel.org/pub/scm/linux/kernel/git/torvalds/linux.git synced 2026-07-16 15:39:42 -04:00
Code Issues Packages Projects Releases Wiki Activity

selftests: net: add test for variable PMTU in broadcast routes

Browse Source 
Added a test for variable PMTU in broadcast routes.

This test uses iputils' ping and attempts to send a ping between
two peers, which should result in a regular echo reply.

This test will fail when the receiving peer does not receive the echo
request due to a lack of packet fragmentation.

Signed-off-by: Oscar Maes <oscmaes92@gmail.com>
Link: https://patch.msgid.link/20250710142714.12986-2-oscmaes92@gmail.com
Signed-off-by: Jakub Kicinski <kuba@kernel.org>
This commit is contained in:
Oscar Maes
2025-07-10 16:27:14 +02:00
committed by Jakub Kicinski
parent 9e30ecf23b
commit 5777d1871b
2 changed files with 48 additions and 0 deletions
Download Patch File Download Diff File Expand all files Collapse all files

1
tools/testing/selftests/net/Makefile
View File

@@ -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_pmtu.sh
# YNL files, must be before "include ..lib.mk"
YNL_GEN_FILES := busy_poller netlink-dumps

47
tools/testing/selftests/net/broadcast_pmtu.sh Executable file
View File

@@ -0,0 +1,47 @@
#!/bin/bash
# SPDX-License-Identifier: GPL-2.0
#
# Ensures broadcast route MTU is respected
CLIENT_NS=$(mktemp -u client-XXXXXXXX)
CLIENT_IP4="192.168.0.1/24"
CLIENT_BROADCAST_ADDRESS="192.168.0.255"
SERVER_NS=$(mktemp -u server-XXXXXXXX)
SERVER_IP4="192.168.0.2/24"
setup() {
ip netns add "${CLIENT_NS}"
ip netns add "${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}" link set link0 mtu 9000
ip -net "${CLIENT_NS}" addr add "${CLIENT_IP4}" dev link0
ip -net "${SERVER_NS}" link set link1 up
ip -net "${SERVER_NS}" link set link1 mtu 1500
ip -net "${SERVER_NS}" addr add "${SERVER_IP4}" dev link1
read -r -a CLIENT_BROADCAST_ENTRY <<< "$(ip -net "${CLIENT_NS}" route show table local type broadcast)"
ip -net "${CLIENT_NS}" route del "${CLIENT_BROADCAST_ENTRY[@]}"
ip -net "${CLIENT_NS}" route add "${CLIENT_BROADCAST_ENTRY[@]}" mtu 1500
ip net exec "${SERVER_NS}" sysctl -wq net.ipv4.icmp_echo_ignore_broadcasts=0
}
cleanup() {
ip -net "${SERVER_NS}" link del link1
ip netns del "${CLIENT_NS}"
ip netns del "${SERVER_NS}"
}
trap cleanup EXIT
setup &&
echo "Testing for broadcast route MTU" &&
ip net exec "${CLIENT_NS}" ping -f -M want -q -c 1 -s 8000 -w 1 -b "${CLIENT_BROADCAST_ADDRESS}" > /dev/null 2>&1
exit $?