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selftests: net: test vxlan pmtu exceptions with tcp

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TCP might get stuck if a nonlinear skb exceeds the path MTU,
icmp error contains an incorrect icmp checksum in that case.

Extend the existing test for vxlan to also send at least 1MB worth of
data via TCP in addition to the existing 'large icmp packet adds
route exception'.

On my test VM this fails due to 0-size output file without
"tunnels: fix kasan splat when generating ipv4 pmtu error".

Signed-off-by: Florian Westphal <fw@strlen.de>
Link: https://lore.kernel.org/r/20230803152653.29535-3-fw@strlen.de
Signed-off-by: Jakub Kicinski <kuba@kernel.org>
This commit is contained in:
Florian Westphal 2023-08-03 17:26:50 +02:00 committed by Jakub Kicinski
parent 6a7ac3d205
commit 136a1b434b
1 changed files with 35 additions and 0 deletions
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35
tools/testing/selftests/net/pmtu.sh
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@ -361,6 +361,7 @@ err_buf=
tcpdump_pids=
nettest_pids=
socat_pids=
tmpoutfile=
err() {
err_buf="${err_buf}${1}
@ -951,6 +952,7 @@ cleanup() {
ip link del veth_A-R1 2>/dev/null
ovs-vsctl --if-exists del-port vxlan_a 2>/dev/null
ovs-vsctl --if-exists del-br ovs_br0 2>/dev/null
rm -f "$tmpoutfile"
}
mtu() {
@ -1328,6 +1330,39 @@ test_pmtu_ipvX_over_bridged_vxlanY_or_geneveY_exception() {
check_pmtu_value ${exp_mtu} "${pmtu}" "exceeding link layer MTU on bridged ${type} interface"
pmtu="$(route_get_dst_pmtu_from_exception "${ns_a}" ${dst})"
check_pmtu_value ${exp_mtu} "${pmtu}" "exceeding link layer MTU on locally bridged ${type} interface"
tmpoutfile=$(mktemp)
# Flush Exceptions, retry with TCP
run_cmd ${ns_a} ip route flush cached ${dst}
run_cmd ${ns_b} ip route flush cached ${dst}
run_cmd ${ns_c} ip route flush cached ${dst}
for target in "${ns_a}" "${ns_c}" ; do
if [ ${family} -eq 4 ]; then
TCPDST=TCP:${dst}:50000
else
TCPDST="TCP:[${dst}]:50000"
fi
${ns_b} socat -T 3 -u -6 TCP-LISTEN:50000 STDOUT > $tmpoutfile &
sleep 1
dd if=/dev/zero of=/dev/stdout status=none bs=1M count=1 | ${target} socat -T 3 -u STDIN $TCPDST,connect-timeout=3
size=$(du -sb $tmpoutfile)
size=${size%%/tmp/*}
[ $size -ne 1048576 ] && err "File size $size mismatches exepcted value in locally bridged vxlan test" && return 1
done
rm -f "$tmpoutfile"
# Check that exceptions were created
pmtu="$(route_get_dst_pmtu_from_exception "${ns_c}" ${dst})"
check_pmtu_value ${exp_mtu} "${pmtu}" "tcp: exceeding link layer MTU on bridged ${type} interface"
pmtu="$(route_get_dst_pmtu_from_exception "${ns_a}" ${dst})"
check_pmtu_value ${exp_mtu} "${pmtu}" "tcp exceeding link layer MTU on locally bridged ${type} interface"
}
test_pmtu_ipv4_br_vxlan4_exception() {