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tools: selftests: add test for changing routes with PTMU exceptions

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Adds new 2 new tests to the PTMU script: pmtu_ipv4/6_route_change.

These tests explicitly test for a recently discovered problem in the
IPv6 routing framework where PMTU exceptions were not properly released
when replacing a route via "ip route change ...".

After creating PMTU exceptions, the route from the device A to R1 will be
replaced with a new route, then device A will be deleted. If the PMTU
exceptions were properly cleaned up by the kernel, this device deletion
will succeed. Otherwise, the unregistration of the device will stall, and
messages such as the following will be logged in dmesg:

unregister_netdevice: waiting for veth_A-R1 to become free. Usage count = 4

Signed-off-by: Sean Tranchetti <stranche@codeaurora.org>
Reviewed-by: David Ahern <dsahern@kernel.org>
Link: https://lore.kernel.org/r/1609892546-11389-2-git-send-email-stranche@quicinc.com
Signed-off-by: Jakub Kicinski <kuba@kernel.org>
This commit is contained in:
Sean Tranchetti 2021-01-05 16:22:26 -08:00 committed by Jakub Kicinski
parent d8f5c29653
commit 5316a7c013
1 changed files with 69 additions and 2 deletions
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71
tools/testing/selftests/net/pmtu.sh
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@ -162,7 +162,15 @@
# - list_flush_ipv6_exception
# Using the same topology as in pmtu_ipv6, create exceptions, and check
# they are shown when listing exception caches, gone after flushing them
#
# - pmtu_ipv4_route_change
# Use the same topology as in pmtu_ipv4, but issue a route replacement
# command and delete the corresponding device afterward. This tests for
# proper cleanup of the PMTU exceptions by the route replacement path.
# Device unregistration should complete successfully
#
# - pmtu_ipv6_route_change
# Same as above but with IPv6
# Kselftest framework requirement - SKIP code is 4.
ksft_skip=4
@ -224,7 +232,9 @@ tests="
cleanup_ipv4_exception ipv4: cleanup of cached exceptions 1
cleanup_ipv6_exception ipv6: cleanup of cached exceptions 1
list_flush_ipv4_exception ipv4: list and flush cached exceptions 1
list_flush_ipv6_exception ipv6: list and flush cached exceptions 1"
list_flush_ipv6_exception ipv6: list and flush cached exceptions 1
pmtu_ipv4_route_change ipv4: PMTU exception w/route replace 1
pmtu_ipv6_route_change ipv6: PMTU exception w/route replace 1"
NS_A="ns-A"
NS_B="ns-B"
@ -1782,6 +1792,63 @@ test_list_flush_ipv6_exception() {
return ${fail}
}
test_pmtu_ipvX_route_change() {
family=${1}
setup namespaces routing || return 2
trace "${ns_a}" veth_A-R1 "${ns_r1}" veth_R1-A \
"${ns_r1}" veth_R1-B "${ns_b}" veth_B-R1 \
"${ns_a}" veth_A-R2 "${ns_r2}" veth_R2-A \
"${ns_r2}" veth_R2-B "${ns_b}" veth_B-R2
if [ ${family} -eq 4 ]; then
ping=ping
dst1="${prefix4}.${b_r1}.1"
dst2="${prefix4}.${b_r2}.1"
gw="${prefix4}.${a_r1}.2"
else
ping=${ping6}
dst1="${prefix6}:${b_r1}::1"
dst2="${prefix6}:${b_r2}::1"
gw="${prefix6}:${a_r1}::2"
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
run_cmd ${ns_a} ${ping} -q -M want -i 0.1 -w 1 -s 1800 ${dst1}
run_cmd ${ns_a} ${ping} -q -M want -i 0.1 -w 1 -s 1800 ${dst2}
# Check that exceptions have been created with the correct PMTU
pmtu_1="$(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
# Replace the route from A to R1
run_cmd ${ns_a} ip route change default via ${gw}
# Delete the device in A
run_cmd ${ns_a} ip link del "veth_A-R1"
}
test_pmtu_ipv4_route_change() {
test_pmtu_ipvX_route_change 4
}
test_pmtu_ipv6_route_change() {
test_pmtu_ipvX_route_change 6
}
usage() {
echo
echo "$0 [OPTIONS] [TEST]..."