linux/tools/testing/selftests/net/pmtu.sh
Stefano Brivio 5e84430bb8 selftests: pmtu: Add test_pmtu_vti4_exception test
This test checks that PMTU exceptions are created only when
needed on IPv4 routes with vti and xfrm, and their PMTU value is
checked as well.

We can't adopt the same approach as test_pmtu_vti6_exception()
here, because on IPv4 administrative MTU changes won't be
reflected directly on PMTU.

Signed-off-by: Stefano Brivio <sbrivio@redhat.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
2018-03-17 20:15:14 -04:00

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#!/bin/sh
# SPDX-License-Identifier: GPL-2.0
#
# Check that route PMTU values match expectations, and that initial device MTU
# values are assigned correctly
#
# Tests currently implemented:
#
# - pmtu_vti4_exception
# Set up vti tunnel on top of veth, with xfrm states and policies, in two
# namespaces with matching endpoints. Check that route exception is not
# created if link layer MTU is not exceeded, then exceed it and check that
# exception is created with the expected PMTU. The approach described
# below for IPv6 doesn't apply here, because, on IPv4, administrative MTU
# changes alone won't affect PMTU
#
# - pmtu_vti6_exception
# Set up vti6 tunnel on top of veth, with xfrm states and policies, in two
# namespaces with matching endpoints. Check that route exception is
# created by exceeding link layer MTU with ping to other endpoint. Then
# decrease and increase MTU of tunnel, checking that route exception PMTU
# changes accordingly
#
# - pmtu_vti4_default_mtu
# Set up vti4 tunnel on top of veth, in two namespaces with matching
# endpoints. Check that MTU assigned to vti interface is the MTU of the
# lower layer (veth) minus additional lower layer headers (zero, for veth)
# minus IPv4 header length
#
# - pmtu_vti6_default_mtu
# Same as above, for IPv6
tests="
pmtu_vti6_exception vti6: PMTU exceptions
pmtu_vti4_exception vti4: PMTU exceptions
pmtu_vti4_default_mtu vti4: default MTU assignment
pmtu_vti6_default_mtu vti6: default MTU assignment"
NS_A="ns-$(mktemp -u XXXXXX)"
NS_B="ns-$(mktemp -u XXXXXX)"
ns_a="ip netns exec ${NS_A}"
ns_b="ip netns exec ${NS_B}"
veth4_a_addr="192.168.1.1"
veth4_b_addr="192.168.1.2"
veth4_mask="24"
veth6_a_addr="fd00:1::a"
veth6_b_addr="fd00:1::b"
veth6_mask="64"
vti4_a_addr="192.168.2.1"
vti4_b_addr="192.168.2.2"
vti4_mask="24"
vti6_a_addr="fd00:2::a"
vti6_b_addr="fd00:2::b"
vti6_mask="64"
cleanup_done=1
err_buf=
err() {
err_buf="${err_buf}${1}
"
}
err_flush() {
echo -n "${err_buf}"
err_buf=
}
setup_namespaces() {
ip netns add ${NS_A} || return 1
ip netns add ${NS_B}
}
setup_veth() {
${ns_a} ip link add veth_a type veth peer name veth_b || return 1
${ns_a} ip link set veth_b netns ${NS_B}
${ns_a} ip addr add ${veth4_a_addr}/${veth4_mask} dev veth_a
${ns_b} ip addr add ${veth4_b_addr}/${veth4_mask} dev veth_b
${ns_a} ip addr add ${veth6_a_addr}/${veth6_mask} dev veth_a
${ns_b} ip addr add ${veth6_b_addr}/${veth6_mask} dev veth_b
${ns_a} ip link set veth_a up
${ns_b} ip link set veth_b up
}
setup_vti() {
proto=${1}
veth_a_addr="${2}"
veth_b_addr="${3}"
vti_a_addr="${4}"
vti_b_addr="${5}"
vti_mask=${6}
[ ${proto} -eq 6 ] && vti_type="vti6" || vti_type="vti"
${ns_a} ip link add vti${proto}_a type ${vti_type} local ${veth_a_addr} remote ${veth_b_addr} key 10 || return 1
${ns_b} ip link add vti${proto}_b type ${vti_type} local ${veth_b_addr} remote ${veth_a_addr} key 10
${ns_a} ip addr add ${vti_a_addr}/${vti_mask} dev vti${proto}_a
${ns_b} ip addr add ${vti_b_addr}/${vti_mask} dev vti${proto}_b
${ns_a} ip link set vti${proto}_a up
${ns_b} ip link set vti${proto}_b up
sleep 1
}
setup_vti4() {
setup_vti 4 ${veth4_a_addr} ${veth4_b_addr} ${vti4_a_addr} ${vti4_b_addr} ${vti4_mask}
}
setup_vti6() {
setup_vti 6 ${veth6_a_addr} ${veth6_b_addr} ${vti6_a_addr} ${vti6_b_addr} ${vti6_mask}
}
setup_xfrm() {
proto=${1}
veth_a_addr="${2}"
veth_b_addr="${3}"
${ns_a} ip -${proto} xfrm state add src ${veth_a_addr} dst ${veth_b_addr} spi 0x1000 proto esp aead "rfc4106(gcm(aes))" 0x0f0f0f0f0f0f0f0f0f0f0f0f0f0f0f0f0f0f0f0f 128 mode tunnel || return 1
${ns_a} ip -${proto} xfrm state add src ${veth_b_addr} dst ${veth_a_addr} spi 0x1001 proto esp aead "rfc4106(gcm(aes))" 0x0f0f0f0f0f0f0f0f0f0f0f0f0f0f0f0f0f0f0f0f 128 mode tunnel
${ns_a} ip -${proto} xfrm policy add dir out mark 10 tmpl src ${veth_a_addr} dst ${veth_b_addr} proto esp mode tunnel
${ns_a} ip -${proto} xfrm policy add dir in mark 10 tmpl src ${veth_b_addr} dst ${veth_a_addr} proto esp mode tunnel
${ns_b} ip -${proto} xfrm state add src ${veth_a_addr} dst ${veth_b_addr} spi 0x1000 proto esp aead "rfc4106(gcm(aes))" 0x0f0f0f0f0f0f0f0f0f0f0f0f0f0f0f0f0f0f0f0f 128 mode tunnel
${ns_b} ip -${proto} xfrm state add src ${veth_b_addr} dst ${veth_a_addr} spi 0x1001 proto esp aead "rfc4106(gcm(aes))" 0x0f0f0f0f0f0f0f0f0f0f0f0f0f0f0f0f0f0f0f0f 128 mode tunnel
${ns_b} ip -${proto} xfrm policy add dir out mark 10 tmpl src ${veth_b_addr} dst ${veth_a_addr} proto esp mode tunnel
${ns_b} ip -${proto} xfrm policy add dir in mark 10 tmpl src ${veth_a_addr} dst ${veth_b_addr} proto esp mode tunnel
}
setup_xfrm4() {
setup_xfrm 4 ${veth4_a_addr} ${veth4_b_addr}
}
setup_xfrm6() {
setup_xfrm 6 ${veth6_a_addr} ${veth6_b_addr}
}
setup() {
[ "$(id -u)" -ne 0 ] && echo " need to run as root" && return 1
cleanup_done=0
for arg do
eval setup_${arg} || { echo " ${arg} not supported"; return 1; }
done
}
cleanup() {
[ ${cleanup_done} -eq 1 ] && return
ip netns del ${NS_A} 2 > /dev/null
ip netns del ${NS_B} 2 > /dev/null
cleanup_done=1
}
mtu() {
ns_cmd="${1}"
dev="${2}"
mtu="${3}"
${ns_cmd} ip link set dev ${dev} mtu ${mtu}
}
mtu_parse() {
input="${1}"
next=0
for i in ${input}; do
[ ${next} -eq 1 ] && echo "${i}" && return
[ "${i}" = "mtu" ] && next=1
done
}
link_get() {
ns_cmd="${1}"
name="${2}"
${ns_cmd} ip link show dev "${name}"
}
link_get_mtu() {
ns_cmd="${1}"
name="${2}"
mtu_parse "$(link_get "${ns_cmd}" ${name})"
}
route_get_dst_exception() {
ns_cmd="${1}"
dst="${2}"
${ns_cmd} ip route get "${dst}"
}
route_get_dst_pmtu_from_exception() {
ns_cmd="${1}"
dst="${2}"
mtu_parse "$(route_get_dst_exception "${ns_cmd}" ${dst})"
}
test_pmtu_vti4_exception() {
setup namespaces veth vti4 xfrm4 || return 2
veth_mtu=1500
vti_mtu=$((veth_mtu - 20))
# SPI SN IV ICV pad length next header
esp_payload_rfc4106=$((vti_mtu - 4 - 4 - 8 - 16 - 1 - 1))
ping_payload=$((esp_payload_rfc4106 - 28))
mtu "${ns_a}" veth_a ${veth_mtu}
mtu "${ns_b}" veth_b ${veth_mtu}
mtu "${ns_a}" vti4_a ${vti_mtu}
mtu "${ns_b}" vti4_b ${vti_mtu}
# Send DF packet without exceeding link layer MTU, check that no
# exception is created
${ns_a} ping -q -M want -i 0.1 -w 2 -s ${ping_payload} ${vti4_b_addr} > /dev/null
pmtu="$(route_get_dst_pmtu_from_exception "${ns_a}" ${vti4_b_addr})"
if [ "${pmtu}" != "" ]; then
err " unexpected exception created with PMTU ${pmtu} for IP payload length ${esp_payload_rfc4106}"
return 1
fi
# Now exceed link layer MTU by one byte, check that exception is created
${ns_a} ping -q -M want -i 0.1 -w 2 -s $((ping_payload + 1)) ${vti4_b_addr} > /dev/null
pmtu="$(route_get_dst_pmtu_from_exception "${ns_a}" ${vti4_b_addr})"
if [ "${pmtu}" = "" ]; then
err " exception not created for IP payload length $((esp_payload_rfc4106 + 1))"
return 1
fi
# ...with the right PMTU value
if [ ${pmtu} -ne ${esp_payload_rfc4106} ]; then
err " wrong PMTU ${pmtu} in exception, expected: ${esp_payload_rfc4106}"
return 1
fi
}
test_pmtu_vti6_exception() {
setup namespaces veth vti6 xfrm6 || return 2
fail=0
# Create route exception by exceeding link layer MTU
mtu "${ns_a}" veth_a 4000
mtu "${ns_b}" veth_b 4000
mtu "${ns_a}" vti6_a 5000
mtu "${ns_b}" vti6_b 5000
${ns_a} ping6 -q -i 0.1 -w 2 -s 60000 ${vti6_b_addr} > /dev/null
# Check that exception was created
if [ "$(route_get_dst_pmtu_from_exception "${ns_a}" ${vti6_b_addr})" = "" ]; then
err " tunnel exceeding link layer MTU didn't create route exception"
return 1
fi
# Decrease tunnel MTU, check for PMTU decrease in route exception
mtu "${ns_a}" vti6_a 3000
if [ "$(route_get_dst_pmtu_from_exception "${ns_a}" ${vti6_b_addr})" -ne 3000 ]; then
err " decreasing tunnel MTU didn't decrease route exception PMTU"
fail=1
fi
# Increase tunnel MTU, check for PMTU increase in route exception
mtu "${ns_a}" vti6_a 9000
if [ "$(route_get_dst_pmtu_from_exception "${ns_a}" ${vti6_b_addr})" -ne 9000 ]; then
err " increasing tunnel MTU didn't increase route exception PMTU"
fail=1
fi
return ${fail}
}
test_pmtu_vti4_default_mtu() {
setup namespaces veth vti4 || return 2
# Check that MTU of vti device is MTU of veth minus IPv4 header length
veth_mtu="$(link_get_mtu "${ns_a}" veth_a)"
vti4_mtu="$(link_get_mtu "${ns_a}" vti4_a)"
if [ $((veth_mtu - vti4_mtu)) -ne 20 ]; then
err " vti MTU ${vti4_mtu} is not veth MTU ${veth_mtu} minus IPv4 header length"
return 1
fi
}
test_pmtu_vti6_default_mtu() {
setup namespaces veth vti6 || return 2
# Check that MTU of vti device is MTU of veth minus IPv6 header length
veth_mtu="$(link_get_mtu "${ns_a}" veth_a)"
vti6_mtu="$(link_get_mtu "${ns_a}" vti6_a)"
if [ $((veth_mtu - vti6_mtu)) -ne 40 ]; then
err " vti MTU ${vti6_mtu} is not veth MTU ${veth_mtu} minus IPv6 header length"
return 1
fi
}
trap cleanup EXIT
exitcode=0
desc=0
IFS="
"
for t in ${tests}; do
[ $desc -eq 0 ] && name="${t}" && desc=1 && continue || desc=0
(
unset IFS
eval test_${name}
ret=$?
cleanup
if [ $ret -eq 0 ]; then
printf "TEST: %-60s [ OK ]\n" "${t}"
elif [ $ret -eq 1 ]; then
printf "TEST: %-60s [FAIL]\n" "${t}"
err_flush
exit 1
elif [ $ret -eq 2 ]; then
printf "TEST: %-60s [SKIP]\n" "${t}"
err_flush
fi
)
[ $? -ne 0 ] && exitcode=1
done
exit ${exitcode}