selftests: add more PMTU tests
Subsystems (3)
cover selftests: add more PMTU tests
The current selftests for PMTU cover VTI tunnels, but there's nothing about the generation and handling of PMTU exceptions by intermediate routers. This series adds and improves existing helpers, then adds IPv4 and IPv6 selftests with a setup involving an intermediate router.
Joint work with Stefano Brivio.
Sabrina Dubroca (2):
selftests: pmtu: extend MTU parsing helper to locked MTU
selftests: pmtu: add basic IPv4 and IPv6 PMTU tests
Stefano Brivio (1):
selftests: pmtu: Introduce check_pmtu_value()
tools/testing/selftests/net/pmtu.sh | 258 ++++++++++++++++++++++++---- 1 file changed, 227 insertions(+), 31 deletions(-)
Signature · 1 line
2.19.0
PATCH 1/3 selftests: pmtu: Introduce check_pmtu_value()
From: Stefano Brivio <[email protected]>
Introduce and use a function that checks PMTU values against expected values and logs error messages, to remove some clutter.
Signed-off-by Stefano Brivio <[email protected]>
Signed-off-by Sabrina Dubroca <[email protected]>
--- tools/testing/selftests/net/pmtu.sh | 49 +++++++++++++---------------- 1 file changed, 22 insertions(+), 27 deletions(-)
tools/testing/selftests/net/pmtu.sh +22 -27
@@ -229,6 +229,19 @@ route_get_dst_pmtu_from_exception() { mtu_parse "$(route_get_dst_exception "${ns_cmd}" ${dst})" } +check_pmtu_value() { + expected="${1}" + value="${2}" + event="${3}" + + [ "${expected}" = "any" ] && [ -n "${value}" ] && return 0 + [ "${value}" = "${expected}" ] && return 0 + [ -z "${value}" ] && err " PMTU exception wasn't created after ${event}" && return 1 + [ -z "${expected}" ] && err " PMTU exception shouldn't exist after ${event}" && return 1 + err " found PMTU exception with incorrect MTU ${value}, expected ${expected}, after ${event}" + return 1 +} + test_pmtu_vti4_exception() { setup namespaces veth vti4 xfrm4 || return 2
@@ -248,24 +261,13 @@ test_pmtu_vti4_exception() { # 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 ${esp_payload_rfc4106}" - return 1 - fi + check_pmtu_value "" "${pmtu}" "sending packet smaller than PMTU (IP payload length ${esp_payload_rfc4106})" || return 1 # Now exceed link layer MTU by one byte, check that exception is created + # with the right PMTU value ${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: ${esp_payload_rfc4106}" - return 1 - fi + check_pmtu_value "${esp_payload_rfc4106}" "${pmtu}" "exceeding PMTU (IP payload length $((esp_payload_rfc4106 + 1)))" } test_pmtu_vti6_exception() {
@@ -280,25 +282,18 @@ test_pmtu_vti6_exception() { ${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}" ${vti6_b_addr})" = "" ]; then - err " tunnel exceeding link layer MTU didn't create route exception" - return 1 - fi + pmtu="$(route_get_dst_pmtu_from_exception "${ns_a}" ${vti6_b_addr})" + check_pmtu_value any "${pmtu}" "creating tunnel exceeding link layer MTU" || return 1 # 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}" ${vti6_b_addr})" -ne 3000 ]; then - err " decreasing tunnel MTU didn't decrease route exception PMTU" - fail=1 - fi + pmtu="$(route_get_dst_pmtu_from_exception "${ns_a}" ${vti6_b_addr})" + check_pmtu_value "3000" "${pmtu}" "decreasing tunnel MTU" || fail=1 # 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}" ${vti6_b_addr})" -ne 9000 ]; then - err " increasing tunnel MTU didn't increase route exception PMTU" - fail=1 - fi + pmtu="$(route_get_dst_pmtu_from_exception "${ns_a}" ${vti6_b_addr})" + check_pmtu_value "9000" "${pmtu}" "increasing tunnel MTU" || fail=1 return ${fail} }
Signature · 1 line
2.19.0
Re: [PATCH net-next 1/3] selftests: pmtu: Introduce check_pmtu_value()
Quoted 11 lines · Sabrina Dubroca
From: Stefano Brivio <[email protected]>
Introduce and use a function that checks PMTU values against expected values and logs error messages, to remove some clutter.
Signed-off-by Stefano Brivio <[email protected]>Signed-off-by Sabrina Dubroca <[email protected]>--- tools/testing/selftests/net/pmtu.sh | 49 +++++++++++++---------------- 1 file changed, 22 insertions(+), 27 deletions(-)
Reviewed-by David Ahern <[email protected]>
PATCH 2/3 selftests: pmtu: extend MTU parsing helper to locked MTU
In reply to Sabrina DubrocaThe mtu_parse helper introduced in commit f2c929feeccd ("selftests:
pmtu: Factor out MTU parsing helper") can only handle "mtu 1234", but not "mtu lock 1234". Extend it, so that we can do IPv4 tests with PMTU smaller than net.ipv4.route.min_pmtu
Signed-off-by Sabrina Dubroca <[email protected]>
--- tools/testing/selftests/net/pmtu.sh | 2 ++ 1 file changed, 2 insertions(+)
tools/testing/selftests/net/pmtu.sh +2 -0
@@ -196,7 +196,9 @@ mtu_parse() { next=0 for i in ${input}; do + [ ${next} -eq 1 -a "${i}" = "lock" ] && next=2 && continue [ ${next} -eq 1 ] && echo "${i}" && return + [ ${next} -eq 2 ] && echo "lock ${i}" && return [ "${i}" = "mtu" ] && next=1 done }
Signature · 1 line
2.19.0
Re: [PATCH net-next 2/3] selftests: pmtu: extend MTU parsing helper to locked MTU
Quoted 10 lines · Sabrina Dubroca
The
mtu_parsehelper introduced in commitf2c929feeccd("selftests:
pmtu: Factor out MTU parsing helper") can only handle "mtu 1234", but not "mtu lock 1234". Extend it, so that we can do IPv4 tests with PMTU smaller than net.ipv4.route.min_pmtuSigned-off-by Sabrina Dubroca <[email protected]>--- tools/testing/selftests/net/pmtu.sh | 2 ++ 1 file changed, 2 insertions(+)
Reviewed-by David Ahern <[email protected]>
PATCH 3/3 selftests: pmtu: add basic IPv4 and IPv6 PMTU tests
In reply to Sabrina DubrocaCommit d1f1b9cbf34c ("selftests: net: Introduce first PMTU test") and follow-ups introduced some PMTU tests, but they all rely on tunneling, and, particularly, on VTI.
These new tests use simple routing to exercise the generation and update of PMTU exceptions in IPv4 and IPv6.
Signed-off-by Sabrina Dubroca <[email protected]>
Signed-off-by Stefano Brivio <[email protected]>
--- tools/testing/selftests/net/pmtu.sh | 207 +++++++++++++++++++++++++++- 1 file changed, 203 insertions(+), 4 deletions(-)
tools/testing/selftests/net/pmtu.sh +203 -4
@@ -6,6 +6,26 @@ # # Tests currently implemented: # +# - pmtu_ipv4 +# Set up two namespaces, A and B, with two paths between them over routers +# R1 and R2 (also implemented with namespaces), with different MTUs: +# +# segment a_r1 segment b_r1 a_r1: 2000 +# .--------------R1--------------. a_r2: 1500 +# A B a_r3: 2000 +# '--------------R2--------------' a_r4: 1400 +# segment a_r2 segment b_r2 +# +# Check that PMTU exceptions with the correct PMTU are created. Then +# decrease and increase the MTU of the local link for one of the paths, +# A to R1, checking that route exception PMTU changes accordingly over +# this path. Also check that locked exceptions are created when an ICMP +# message advertising a PMTU smaller than net.ipv4.route.min_pmtu is +# received +# +# - pmtu_ipv6 +# Same as pmtu_ipv4, except for locked PMTU tests, using IPv6 +# # - 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
@@ -50,6 +70,8 @@ ksft_skip=4 which ping6 > /dev/null 2>&1 && ping6=$(which ping6) || ping6=$(which ping) tests=" + pmtu_ipv4_exception ipv4: PMTU exceptions + pmtu_ipv6_exception ipv6: PMTU exceptions pmtu_vti6_exception vti6: PMTU exceptions pmtu_vti4_exception vti4: PMTU exceptions pmtu_vti4_default_mtu vti4: default MTU assignment
@@ -60,8 +82,45 @@ tests=" NS_A="ns-$(mktemp -u XXXXXX)" NS_B="ns-$(mktemp -u XXXXXX)" +NS_R1="ns-$(mktemp -u XXXXXX)" +NS_R2="ns-$(mktemp -u XXXXXX)" ns_a="ip netns exec ${NS_A}" ns_b="ip netns exec ${NS_B}" +ns_r1="ip netns exec ${NS_R1}" +ns_r2="ip netns exec ${NS_R2}" + +# Addressing and routing for tests with routers: four network segments, with +# index SEGMENT between 1 and 4, a common prefix (PREFIX4 or PREFIX6) and an +# identifier ID, which is 1 for hosts (A and B), 2 for routers (R1 and R2). +# Addresses are: +# - IPv4: PREFIX4.SEGMENT.ID (/24) +# - IPv6: PREFIX6:SEGMENT::ID (/64) +prefix4="192.168" +prefix6="fd00" +a_r1=1 +a_r2=2 +b_r1=3 +b_r2=4 +# ns peer segment +routing_addrs=" + A R1 ${a_r1} + A R2 ${a_r2} + B R1 ${b_r1} + B R2 ${b_r2} +" +# Traffic from A to B goes through R1 by default, and through R2, if destined to +# B's address on the b_r2 segment. +# Traffic from B to A goes through R1. +# ns destination gateway +routes=" + A default ${prefix4}.${a_r1}.2 + A ${prefix4}.${b_r2}.1 ${prefix4}.${a_r2}.2 + B default ${prefix4}.${b_r1}.2 + + A default ${prefix6}:${a_r1}::2 + A ${prefix6}:${b_r2}::1 ${prefix6}:${a_r2}::2 + B default ${prefix6}:${b_r1}::2 +" veth4_a_addr="192.168.1.1" veth4_b_addr="192.168.1.2"
@@ -94,9 +153,15 @@ err_flush() { err_buf= } +# Find the auto-generated name for this namespace +nsname() { + eval echo \$NS_$1 +} + setup_namespaces() { - ip netns add ${NS_A} || return 1 - ip netns add ${NS_B} + for n in ${NS_A} ${NS_B} ${NS_R1} ${NS_R2}; do + ip netns add ${n} || return 1 + done } setup_veth() {
@@ -167,6 +232,49 @@ setup_xfrm6() { setup_xfrm 6 ${veth6_a_addr} ${veth6_b_addr} } +setup_routing() { + for i in ${NS_R1} ${NS_R2}; do + ip netns exec ${i} sysctl -q net/ipv4/ip_forward=1 + ip netns exec ${i} sysctl -q net/ipv6/conf/all/forwarding=1 + done + + for i in ${routing_addrs}; do + [ "${ns}" = "" ] && ns="${i}" && continue + [ "${peer}" = "" ] && peer="${i}" && continue + [ "${segment}" = "" ] && segment="${i}" + + ns_name="$(nsname ${ns})" + peer_name="$(nsname ${peer})" + if="veth_${ns}-${peer}" + ifpeer="veth_${peer}-${ns}" + + # Create veth links + ip link add ${if} up netns ${ns_name} type veth peer name ${ifpeer} netns ${peer_name} || return 1 + ip -n ${peer_name} link set dev ${ifpeer} up + + # Add addresses + ip -n ${ns_name} addr add ${prefix4}.${segment}.1/24 dev ${if} + ip -n ${ns_name} addr add ${prefix6}:${segment}::1/64 dev ${if} + + ip -n ${peer_name} addr add ${prefix4}.${segment}.2/24 dev ${ifpeer} + ip -n ${peer_name} addr add ${prefix6}:${segment}::2/64 dev ${ifpeer} + + ns=""; peer=""; segment="" + done + + for i in ${routes}; do + [ "${ns}" = "" ] && ns="${i}" && continue + [ "${addr}" = "" ] && addr="${i}" && continue + [ "${gw}" = "" ] && gw="${i}" + + ns_name="$(nsname ${ns})" + + ip -n ${ns_name} route add ${addr} via ${gw} + + ns=""; addr=""; gw="" + done +} + setup() { [ "$(id -u)" -ne 0 ] && echo " need to run as root" && return $ksft_skip
@@ -178,8 +286,9 @@ setup() { cleanup() { [ ${cleanup_done} -eq 1 ] && return - ip netns del ${NS_A} 2> /dev/null - ip netns del ${NS_B} 2> /dev/null + for n in ${NS_A} ${NS_B} ${NS_R1} ${NS_R2}; do + ip netns del ${n} 2> /dev/null + done cleanup_done=1 }
@@ -244,6 +353,96 @@ check_pmtu_value() { return 1 } +test_pmtu_ipvX() { + family=${1} + + setup namespaces routing || return 2 + + if [ ${family} -eq 4 ]; then + ping=ping + dst1="${prefix4}.${b_r1}.1" + dst2="${prefix4}.${b_r2}.1" + else + ping=${ping6} + dst1="${prefix6}:${b_r1}::1" + dst2="${prefix6}:${b_r2}::1" + fi + + # Set up initial MTU values + mtu "${ns_a}" veth_A-R1 2000 + mtu "${ns_r1}" veth_R1-A 2000 + mtu "${ns_r1}" veth_R1-B 1400 + mtu "${ns_b}" veth_B-R1 1400 + + mtu "${ns_a}" veth_A-R2 2000 + mtu "${ns_r2}" veth_R2-A 2000 + mtu "${ns_r2}" veth_R2-B 1500 + mtu "${ns_b}" veth_B-R2 1500 + + # Create route exceptions + ${ns_a} ${ping} -q -M want -i 0.1 -w 2 -s 1800 ${dst1} > /dev/null + ${ns_a} ${ping} -q -M want -i 0.1 -w 2 -s 1800 ${dst2} > /dev/null + + # Check that exceptions have been created with the correct PMTU + pmtu_1="$(route_get_dst_pmtu_from_exception "${ns_a}" ${dst1})" + check_pmtu_value "1400" "${pmtu_1}" "exceeding MTU" || return 1 + pmtu_2="$(route_get_dst_pmtu_from_exception "${ns_a}" ${dst2})" + check_pmtu_value "1500" "${pmtu_2}" "exceeding MTU" || return 1 + + # Decrease local MTU below PMTU, check for PMTU decrease in route exception + mtu "${ns_a}" veth_A-R1 1300 + mtu "${ns_r1}" veth_R1-A 1300 + pmtu_1="$(route_get_dst_pmtu_from_exception "${ns_a}" ${dst1})" + check_pmtu_value "1300" "${pmtu_1}" "decreasing local MTU" || return 1 + # Second exception shouldn't be modified + pmtu_2="$(route_get_dst_pmtu_from_exception "${ns_a}" ${dst2})" + check_pmtu_value "1500" "${pmtu_2}" "changing local MTU on a link not on this path" || return 1 + + # Increase MTU, check for PMTU increase in route exception + mtu "${ns_a}" veth_A-R1 1700 + mtu "${ns_r1}" veth_R1-A 1700 + pmtu_1="$(route_get_dst_pmtu_from_exception "${ns_a}" ${dst1})" + check_pmtu_value "1700" "${pmtu_1}" "increasing local MTU" || return 1 + # Second exception shouldn't be modified + pmtu_2="$(route_get_dst_pmtu_from_exception "${ns_a}" ${dst2})" + check_pmtu_value "1500" "${pmtu_2}" "changing local MTU on a link not on this path" || return 1 + + # Skip PMTU locking tests for IPv6 + [ $family -eq 6 ] && return 0 + + # Decrease remote MTU on path via R2, get new exception + mtu "${ns_r2}" veth_R2-B 400 + mtu "${ns_b}" veth_B-R2 400 + ${ns_a} ${ping} -q -M want -i 0.1 -w 2 -s 1400 ${dst2} > /dev/null + pmtu_2="$(route_get_dst_pmtu_from_exception "${ns_a}" ${dst2})" + check_pmtu_value "lock 552" "${pmtu_2}" "exceeding MTU, with MTU < min_pmtu" || return 1 + + # Decrease local MTU below PMTU + mtu "${ns_a}" veth_A-R2 500 + mtu "${ns_r2}" veth_R2-A 500 + pmtu_2="$(route_get_dst_pmtu_from_exception "${ns_a}" ${dst2})" + check_pmtu_value "500" "${pmtu_2}" "decreasing local MTU" || return 1 + + # Increase local MTU + mtu "${ns_a}" veth_A-R2 1500 + mtu "${ns_r2}" veth_R2-A 1500 + pmtu_2="$(route_get_dst_pmtu_from_exception "${ns_a}" ${dst2})" + check_pmtu_value "1500" "${pmtu_2}" "increasing local MTU" || return 1 + + # Get new exception + ${ns_a} ${ping} -q -M want -i 0.1 -w 2 -s 1400 ${dst2} > /dev/null + pmtu_2="$(route_get_dst_pmtu_from_exception "${ns_a}" ${dst2})" + check_pmtu_value "lock 552" "${pmtu_2}" "exceeding MTU, with MTU < min_pmtu" || return 1 +} + +test_pmtu_ipv4_exception() { + test_pmtu_ipvX 4 +} + +test_pmtu_ipv6_exception() { + test_pmtu_ipvX 6 +} + test_pmtu_vti4_exception() { setup namespaces veth vti4 xfrm4 || return 2
Signature · 1 line
2.19.0
Re: [PATCH net-next 3/3] selftests: pmtu: add basic IPv4 and IPv6 PMTU tests
Quoted 4 lines · Sabrina Dubroca
Commit
d1f1b9cbf34c("selftests: net: Introduce first PMTU test") and follow-ups introduced some PMTU tests, but they all rely on tunneling, and, particularly, on VTI.
Quoted 9 lines
These new tests use simple routing to exercise the generation and update of PMTU exceptions in IPv4 and IPv6.
Signed-off-by Sabrina Dubroca <[email protected]>Signed-off-by Stefano Brivio <[email protected]>--- tools/testing/selftests/net/pmtu.sh | 207 +++++++++++++++++++++++++++- 1 file changed, 203 insertions(+), 4 deletions(-)
Thanks for adding more pmtu tests.
Reviewed-by David Ahern <[email protected]>
David Miller
maintainerFrom: Sabrina Dubroca <[email protected]>
Date: Mon, 8 Oct 2018 14:37:02 +0200
Quoted 6 lines
The current selftests for PMTU cover VTI tunnels, but there's nothing about the generation and handling of PMTU exceptions by intermediate routers. This series adds and improves existing helpers, then adds IPv4 and IPv6 selftests with a setup involving an intermediate router.
Joint work with Stefano Brivio.
This is really great stuff to see.
Series applied, thanks.