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kernel
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linux
selftests: forwarding: Add test for minimum and maximum MTU
Add cases to check minimum and maximum MTU which are exposed via
"ip -d link show". Test configuration and traffic. Use VLAN devices as
usually VLAN header (4 bytes) is not included in the MTU, and drivers
should configure hardware correctly to send maximum MTU payload size
in VLAN tagged packets.
$ ./min_max_mtu.sh
TEST: ping [ OK ]
TEST: ping6 [ OK ]
TEST: Test maximum MTU configuration [ OK ]
TEST: Test traffic, packet size is maximum MTU [ OK ]
TEST: Test minimum MTU configuration [ OK ]
TEST: Test traffic, packet size is minimum MTU [ OK ]
Signed-off-by: Amit Cohen <amcohen@nvidia.com>
Reviewed-by: Petr Machata <petrm@nvidia.com>
Signed-off-by: Petr Machata <petrm@nvidia.com>
Link: https://lore.kernel.org/r/89de8be8989db7a97f3b39e3c9da695673e78d2e.1718275854.git.petrm@nvidia.com
Signed-off-by: Jakub Kicinski <kuba@kernel.org>
authored by
Amit Cohen
and committed by
Jakub Kicinski
4be3dcc9
3e785654
+284
+1
tools/testing/selftests/net/forwarding/Makefile
+1
tools/testing/selftests/net/forwarding/Makefile
+283
tools/testing/selftests/net/forwarding/min_max_mtu.sh
+283
tools/testing/selftests/net/forwarding/min_max_mtu.sh
···
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#!/bin/bash
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# SPDX-License-Identifier: GPL-2.0
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# +--------------------+
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# | H1 |
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# | |
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# | $h1.10 + |
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# | 192.0.2.2/24 | |
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# | 2001:db8:1::2/64 | |
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# | | |
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# | $h1 + |
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# | | |
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# +------------------|-+
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# |
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# +------------------|-+
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# | SW | |
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# | $swp1 + |
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# | | |
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# | $swp1.10 + |
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# | 192.0.2.1/24 |
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# | 2001:db8:1::1/64 |
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# | |
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# +--------------------+
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ALL_TESTS="
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ping_ipv4
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ping_ipv6
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max_mtu_config_test
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max_mtu_traffic_test
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min_mtu_config_test
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min_mtu_traffic_test
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"
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NUM_NETIFS=2
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source lib.sh
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h1_create()
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{
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simple_if_init $h1
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vlan_create $h1 10 v$h1 192.0.2.2/24 2001:db8:1::2/64
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}
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h1_destroy()
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{
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vlan_destroy $h1 10 192.0.2.2/24 2001:db8:1::2/64
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simple_if_fini $h1
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}
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switch_create()
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{
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ip li set dev $swp1 up
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vlan_create $swp1 10 "" 192.0.2.1/24 2001:db8:1::1/64
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}
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switch_destroy()
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{
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ip li set dev $swp1 down
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vlan_destroy $swp1 10
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}
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setup_prepare()
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{
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h1=${NETIFS[p1]}
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swp1=${NETIFS[p2]}
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vrf_prepare
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h1_create
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switch_create
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forwarding_enable
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}
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cleanup()
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{
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pre_cleanup
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forwarding_restore
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switch_destroy
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h1_destroy
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vrf_cleanup
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}
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ping_ipv4()
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{
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ping_test $h1.10 192.0.2.1
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}
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ping_ipv6()
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{
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ping6_test $h1.10 2001:db8:1::1
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}
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min_max_mtu_get_if()
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{
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local dev=$1; shift
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local min_max=$1; shift
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ip -d -j link show $dev | jq ".[].$min_max"
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}
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ensure_compatible_min_max_mtu()
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{
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local min_max=$1; shift
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local mtu=$(min_max_mtu_get_if ${NETIFS[p1]} $min_max)
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local i
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for ((i = 2; i <= NUM_NETIFS; ++i)); do
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local current_mtu=$(min_max_mtu_get_if ${NETIFS[p$i]} $min_max)
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if [ $current_mtu -ne $mtu ]; then
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return 1
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fi
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done
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}
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mtu_set_if()
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{
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local dev=$1; shift
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local mtu=$1; shift
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local should_fail=${1:-0}; shift
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mtu_set $dev $mtu 2>/dev/null
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check_err_fail $should_fail $? "Set MTU $mtu for $dev"
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}
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mtu_set_all_if()
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{
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local mtu=$1; shift
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local i
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for ((i = 1; i <= NUM_NETIFS; ++i)); do
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mtu_set_if ${NETIFS[p$i]} $mtu
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mtu_set_if ${NETIFS[p$i]}.10 $mtu
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done
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}
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mtu_restore_all_if()
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{
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local i
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for ((i = 1; i <= NUM_NETIFS; ++i)); do
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mtu_restore ${NETIFS[p$i]}.10
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mtu_restore ${NETIFS[p$i]}
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done
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}
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mtu_test_ping4()
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{
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local mtu=$1; shift
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local should_fail=$1; shift
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# Ping adds 8 bytes for ICMP header and 20 bytes for IP header
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local ping_headers_len=$((20 + 8))
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local pkt_size=$((mtu - ping_headers_len))
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ping_do $h1.10 192.0.2.1 "-s $pkt_size -M do"
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check_err_fail $should_fail $? "Ping, packet size: $pkt_size"
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}
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mtu_test_ping6()
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{
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local mtu=$1; shift
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local should_fail=$1; shift
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# Ping adds 8 bytes for ICMP header and 40 bytes for IPv6 header
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local ping6_headers_len=$((40 + 8))
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local pkt_size=$((mtu - ping6_headers_len))
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ping6_do $h1.10 2001:db8:1::1 "-s $pkt_size -M do"
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check_err_fail $should_fail $? "Ping6, packet size: $pkt_size"
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}
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max_mtu_config_test()
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{
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local i
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RET=0
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for ((i = 1; i <= NUM_NETIFS; ++i)); do
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local dev=${NETIFS[p$i]}
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local max_mtu=$(min_max_mtu_get_if $dev "max_mtu")
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local should_fail
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should_fail=0
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mtu_set_if $dev $max_mtu $should_fail
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mtu_restore $dev
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should_fail=1
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mtu_set_if $dev $((max_mtu + 1)) $should_fail
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mtu_restore $dev
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done
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log_test "Test maximum MTU configuration"
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}
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max_mtu_traffic_test()
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{
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local should_fail
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local max_mtu
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RET=0
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if ! ensure_compatible_min_max_mtu "max_mtu"; then
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log_test_xfail "Topology has incompatible maximum MTU values"
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return
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fi
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max_mtu=$(min_max_mtu_get_if ${NETIFS[p1]} "max_mtu")
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should_fail=0
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mtu_set_all_if $max_mtu
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mtu_test_ping4 $max_mtu $should_fail
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mtu_test_ping6 $max_mtu $should_fail
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mtu_restore_all_if
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should_fail=1
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mtu_set_all_if $((max_mtu - 1))
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mtu_test_ping4 $max_mtu $should_fail
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mtu_test_ping6 $max_mtu $should_fail
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mtu_restore_all_if
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log_test "Test traffic, packet size is maximum MTU"
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}
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min_mtu_config_test()
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{
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local i
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RET=0
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for ((i = 1; i <= NUM_NETIFS; ++i)); do
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local dev=${NETIFS[p$i]}
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local min_mtu=$(min_max_mtu_get_if $dev "min_mtu")
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local should_fail
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should_fail=0
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mtu_set_if $dev $min_mtu $should_fail
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mtu_restore $dev
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should_fail=1
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mtu_set_if $dev $((min_mtu - 1)) $should_fail
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mtu_restore $dev
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done
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log_test "Test minimum MTU configuration"
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}
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min_mtu_traffic_test()
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{
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local should_fail=0
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local min_mtu
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RET=0
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if ! ensure_compatible_min_max_mtu "min_mtu"; then
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log_test_xfail "Topology has incompatible minimum MTU values"
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return
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fi
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min_mtu=$(min_max_mtu_get_if ${NETIFS[p1]} "min_mtu")
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mtu_set_all_if $min_mtu
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mtu_test_ping4 $min_mtu $should_fail
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# Do not test minimum MTU with IPv6, as IPv6 requires higher MTU.
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mtu_restore_all_if
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log_test "Test traffic, packet size is minimum MTU"
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}
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trap cleanup EXIT
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setup_prepare
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setup_wait
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tests_run
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exit $EXIT_STATUS