#!/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
#
# - pmtu_vti4_link_add_mtu
# Set up vti4 interface passing MTU value at link creation, check MTU is
# configured, and that link is not created with invalid MTU values
#
# - pmtu_vti6_link_add_mtu
# Same as above, for IPv6
#
# - pmtu_vti6_link_change_mtu
# Set up two dummy interfaces with different MTUs, create a vti6 tunnel
# and check that configured MTU is used on link creation and changes, and
# that MTU is properly calculated instead when MTU is not configured from
# userspace
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
pmtu_vti4_link_add_mtu vti4: MTU setting on link creation
pmtu_vti6_link_add_mtu vti6: MTU setting on link creation
pmtu_vti6_link_change_mtu vti6: MTU changes on link changes"
NS_A="ns-$(mktemp -u XXXXXX)"
NS_B="ns-$(mktemp -u XXXXXX)"
ns_a="ip netns exec ${NS_A}"
ns_b="ip netns exec ${NS_B}"
veth4_a_addr="192.168.1.1"
veth4_b_addr="192.168.1.2"
veth4_mask="24"
veth6_a_addr="fd00:1::a"
veth6_b_addr="fd00:1::b"
veth6_mask="64"
vti4_a_addr="192.168.2.1"
vti4_b_addr="192.168.2.2"
vti4_mask="24"
vti6_a_addr="fd00:2::a"
vti6_b_addr="fd00:2::b"
vti6_mask="64"
dummy6_0_addr="fc00:1000::0"
dummy6_1_addr="fc00:1001::0"
dummy6_mask="64"
cleanup_done=1
err_buf=
err() {
err_buf="${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
}
test_pmtu_vti4_link_add_mtu() {
setup namespaces || return 2
${ns_a} ip link add vti4_a type vti local ${veth4_a_addr} remote ${veth4_b_addr} key 10
[ $? -ne 0 ] && err " vti not supported" && return 2
${ns_a} ip link del vti4_a
fail=0
min=68
max=$((65528 - 20))
# Check invalid values first
for v in $((min - 1)) $((max + 1)); do
${ns_a} ip link add vti4_a mtu ${v} type vti local ${veth4_a_addr} remote ${veth4_b_addr} key 10 2>/dev/null
# This can fail, or MTU can be adjusted to a proper value
[ $? -ne 0 ] && continue
mtu="$(link_get_mtu "${ns_a}" vti4_a)"
if [ ${mtu} -lt ${min} -o ${mtu} -gt ${max} ]; then
err " vti tunnel created with invalid MTU ${mtu}"
fail=1
fi
${ns_a} ip link del vti4_a
done
# Now check valid values
for v in ${min} 1300 ${max}; do
${ns_a} ip link add vti4_a mtu ${v} type vti local ${veth4_a_addr} remote ${veth4_b_addr} key 10
mtu="$(link_get_mtu "${ns_a}" vti4_a)"
${ns_a} ip link del vti4_a
if [ "${mtu}" != "${v}" ]; then
err " vti MTU ${mtu} doesn't match configured value ${v}"
fail=1
fi
done
return ${fail}
}
test_pmtu_vti6_link_add_mtu() {
setup namespaces || return 2
${ns_a} ip link add vti6_a type vti6 local ${veth6_a_addr} remote ${veth6_b_addr} key 10
[ $? -ne 0 ] && err " vti6 not supported" && return 2
${ns_a} ip link del vti6_a
fail=0
min=1280
max=$((65535 - 40))
# Check invalid values first
for v in $((min - 1)) $((max + 1)); do
${ns_a} ip link add vti6_a mtu ${v} type vti6 local ${veth6_a_addr} remote ${veth6_b_addr} key 10 2>/dev/null
# This can fail, or MTU can be adjusted to a proper value
[ $? -ne 0 ] && continue
mtu="$(link_get_mtu "${ns_a}" vti6_a)"
if [ ${mtu} -lt ${min} -o ${mtu} -gt ${max} ]; then
err " vti6 tunnel created with invalid MTU ${v}"
fail=1
fi
${ns_a} ip link del vti6_a
done
# Now check valid values
for v in 1280 1300 $((65535 - 40)); do
${ns_a} ip link add vti6_a mtu ${v} type vti6 local ${veth6_a_addr} remote ${veth6_b_addr} key 10
mtu="$(link_get_mtu "${ns_a}" vti6_a)"
${ns_a} ip link del vti6_a
if [ "${mtu}" != "${v}" ]; then
err " vti6 MTU ${mtu} doesn't match configured value ${v}"
fail=1
fi
done
return ${fail}
}
test_pmtu_vti6_link_change_mtu() {
setup namespaces || return 2
${ns_a} ip link add dummy0 mtu 1500 type dummy
[ $? -ne 0 ] && err " dummy not supported" && return 2
${ns_a} ip link add dummy1 mtu 3000 type dummy
${ns_a} ip link set dummy0 up
${ns_a} ip link set dummy1 up
${ns_a} ip addr add ${dummy6_0_addr}/${dummy6_mask} dev dummy0
${ns_a} ip addr add ${dummy6_1_addr}/${dummy6_mask} dev dummy1
fail=0
# Create vti6 interface bound to device, passing MTU, check it
${ns_a} ip link add vti6_a mtu 1300 type vti6 remote ${dummy6_0_addr} local ${dummy6_0_addr}
mtu="$(link_get_mtu "${ns_a}" vti6_a)"
if [ ${mtu} -ne 1300 ]; then
err " vti6 MTU ${mtu} doesn't match configured value 1300"
fail=1
fi
# Move to another device with different MTU, without passing MTU, check
# MTU is adjusted
${ns_a} ip link set vti6_a type vti6 remote ${dummy6_1_addr} local ${dummy6_1_addr}
mtu="$(link_get_mtu "${ns_a}" vti6_a)"
if [ ${mtu} -ne $((3000 - 40)) ]; then
err " vti MTU ${mtu} is not dummy MTU 3000 minus IPv6 header length"
fail=1
fi
# Move it back, passing MTU, check MTU is not overridden
${ns_a} ip link set vti6_a mtu 1280 type vti6 remote ${dummy6_0_addr} local ${dummy6_0_addr}
mtu="$(link_get_mtu "${ns_a}" vti6_a)"
if [ ${mtu} -ne 1280 ]; then
err " vti6 MTU ${mtu} doesn't match configured value 1280"
fail=1
fi
return ${fail}
}
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}
