Commit 136a1b43 authored by Florian Westphal's avatar Florian Westphal Committed by Jakub Kicinski
Browse files

selftests: net: test vxlan pmtu exceptions with tcp 



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: default avatarFlorian Westphal <fw@strlen.de>
Link: https://lore.kernel.org/r/20230803152653.29535-3-fw@strlen.de


Signed-off-by: default avatarJakub Kicinski <kuba@kernel.org>
parent 6a7ac3d2

tools/testing/selftests/net/pmtu.sh

+35 −0
Original line number Diff line number Diff line
@@ -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() {