selftests: net: more pmtu.sh fixes

The netdev CI is reporting failures for the pmtu test:

[ 115.929264] br0: port 2(vxlan_a) entered forwarding state
# 2024/02/08 17:33:22 socat[7871] E bind(7, {AF=10 [0000:0000:0000:0000:0000:0000:0000:0000]:50000}, 28): Address already in use
# 2024/02/08 17:33:22 socat[7877] E write(7, 0x5598fb6ff000, 8192): Connection refused
# TEST: IPv6, bridged vxlan4: PMTU exceptions [FAIL]
# File size 0 mismatches exepcted value in locally bridged vxlan test

The root cause is apparently a socket created by a previous iteration
of the relevant loop still lasting in LAST_ACK state.

Note that even the file size check is racy, the receiver process dumping
the file could still be running in background

Allow the listener to bound on the same local port via SO_REUSEADDR and
collect file output file size only after the listener completion.

Fixes: 136a1b434bbb ("selftests: net: test vxlan pmtu exceptions with tcp")
Signed-off-by: Paolo Abeni <pabeni@redhat.com>
Link: https://lore.kernel.org/r/4f51c11a1ce7ca7a4dabd926cffff63dadac9ba1.1707731086.git.pabeni@redhat.com
Signed-off-by: Jakub Kicinski <kuba@kernel.org>

selftests: net: avoid just another constant wait

Using hard-coded constant timeout to wait for some expected
event is deemed to fail sooner or later, especially in slow
env.

Our CI has spotted another of such race:
# TEST: ipv6: cleanup of cached exceptions - nexthop objects [FAIL]
# can't delete veth device in a timely manner, PMTU dst likely leaked

Replace the crude sleep with a loop looking for the expected condition
at low interval for a much longer range.

Fixes: b3cc4f8a8a41 ("selftests: pmtu: add explicit tests for PMTU exceptions cleanup")
Signed-off-by: Paolo Abeni <pabeni@redhat.com>
Reviewed-by: David Ahern <dsahern@kernel.org>
Link: https://lore.kernel.org/r/fd5c745e9bb665b724473af6a9373a8c2a62b247.1706812005.git.pabeni@redhat.com
Signed-off-by: Jakub Kicinski <kuba@kernel.org>

selftests: net: fix tcp listener handling in pmtu.sh

The pmtu.sh test uses a few TCP listener in a problematic way:
It hard-codes a constant timeout to wait for the listener starting-up
in background. That introduces unneeded latency and on very slow and
busy host it can fail.

Additionally the test starts again the same listener in the same
namespace on the same port, just after the previous connection
completed. Fast host can attempt starting the new server before the
old one really closed the socket.

Address the issues using the wait_local_port_listen helper and
explicitly waiting for the background listener process exit.

Fixes: 136a1b434bbb ("selftests: net: test vxlan pmtu exceptions with tcp")
Signed-off-by: Paolo Abeni <pabeni@redhat.com>
Reviewed-by: David Ahern <dsahern@kernel.org>
Link: https://lore.kernel.org/r/f8e8f6d44427d8c45e9f6a71ee1a321047452087.1706812005.git.pabeni@redhat.com
Signed-off-by: Jakub Kicinski <kuba@kernel.org>

selftests: net: don't access /dev/stdout in pmtu.sh

When running the pmtu.sh via the kselftest infra, accessing
/dev/stdout gives unexpected results:
# dd: failed to open '/dev/stdout': Device or resource busy
# TEST: IPv4, bridged vxlan4: PMTU exceptions [FAIL]

Let dd use directly the standard output to fix the above:
# TEST: IPv4, bridged vxlan4: PMTU exceptions - nexthop objects [ OK ]

Fixes: 136a1b434bbb ("selftests: net: test vxlan pmtu exceptions with tcp")
Signed-off-by: Paolo Abeni <pabeni@redhat.com>
Reviewed-by: Guillaume Nault <gnault@redhat.com>
Reviewed-by: David Ahern <dsahern@kernel.org>
Link: https://lore.kernel.org/r/23d7592c5d77d75cff9b34f15c227f92e911c2ae.1706635101.git.pabeni@redhat.com
Signed-off-by: Jakub Kicinski <kuba@kernel.org>

selftests: net: fix available tunnels detection

The pmtu.sh test tries to detect the tunnel protocols available
in the running kernel and properly skip the unsupported cases.

In a few more complex setup, such detection is unsuccessful, as
the script currently ignores some intermediate error code at
setup time.

Before:
# which: no nettest in (/bin:/sbin:/usr/bin:/usr/sbin:/usr/local/bin)
# TEST: vti6: PMTU exceptions (ESP-in-UDP) [FAIL]
# PMTU exception wasn't created after creating tunnel exceeding link layer MTU
# ./pmtu.sh: line 931: kill: (7543) - No such process
# ./pmtu.sh: line 931: kill: (7544) - No such process

After:
# xfrm4 not supported
# TEST: vti4: PMTU exceptions [SKIP]

Fixes: ece1278a9b81 ("selftests: net: add ESP-in-UDP PMTU test")
Signed-off-by: Paolo Abeni <pabeni@redhat.com>
Reviewed-by: Guillaume Nault <gnault@redhat.com>
Reviewed-by: David Ahern <dsahern@kernel.org>
Link: https://lore.kernel.org/r/cab10e75fda618e6fff8c595b632f47db58b9309.1706635101.git.pabeni@redhat.com
Signed-off-by: Jakub Kicinski <kuba@kernel.org>

selftests/net: change shebang to bash to support "source"

The patch set [1] added a general lib.sh in net selftests, and converted
several test scripts to source the lib.sh.

unicast_extensions.sh (converted in [1]) and pmtu.sh (converted in [2])
have a /bin/sh shebang which may point to various shells in different
distributions, but "source" is only available in some of them. For
example, "source" is a built-it function in bash, but it cannot be
used in dash.

Refer to other scripts that were converted together, simply change the
shebang to bash to fix the following issues when the default /bin/sh
points to other shells.

not ok 51 selftests: net: unicast_extensions.sh # exit=1

v1 -> v2:
- Fix pmtu.sh which has the same issue as unicast_extensions.sh,
suggested by Hangbin
- Change the style of the "source" line to be consistent with other
tests, suggested by Hangbin

Link: https://lore.kernel.org/all/20231202020110.362433-1-liuhangbin@gmail.com/ [1]
Link: https://lore.kernel.org/all/20231219094856.1740079-1-liuhangbin@gmail.com/ [2]
Reported-by: kernel test robot <oliver.sang@intel.com>
Fixes: 378f082eaf37 ("selftests/net: convert pmtu.sh to run it in unique namespace")
Fixes: 0f4765d0b48d ("selftests/net: convert unicast_extensions.sh to run it in unique namespace")
Signed-off-by: Yujie Liu <yujie.liu@intel.com>
Reviewed-by: Przemek Kitszel <przemyslaw.kitszel@intel.com>
Reviewed-by: Hangbin Liu <liuhangbin@gmail.com>
Reviewed-by: Muhammad Usama Anjum <usama.anjum@collabora.com>
Link: https://lore.kernel.org/r/20231229131931.3961150-1-yujie.liu@intel.com
Signed-off-by: Jakub Kicinski <kuba@kernel.org>

selftests/net: convert pmtu.sh to run it in unique namespace

pmtu test use /bin/sh, so we need to source ./lib.sh instead of lib.sh
Here is the test result after conversion.

# ./pmtu.sh
TEST: ipv4: PMTU exceptions [ OK ]
TEST: ipv4: PMTU exceptions - nexthop objects [ OK ]
TEST: ipv6: PMTU exceptions [ OK ]
TEST: ipv6: PMTU exceptions - nexthop objects [ OK ]
...
TEST: ipv4: list and flush cached exceptions - nexthop objects [ OK ]
TEST: ipv6: list and flush cached exceptions [ OK ]
TEST: ipv6: list and flush cached exceptions - nexthop objects [ OK ]
TEST: ipv4: PMTU exception w/route replace [ OK ]
TEST: ipv4: PMTU exception w/route replace - nexthop objects [ OK ]
TEST: ipv6: PMTU exception w/route replace [ OK ]
TEST: ipv6: PMTU exception w/route replace - nexthop objects [ OK ]

Signed-off-by: Hangbin Liu <liuhangbin@gmail.com>
Signed-off-by: David S. Miller <davem@davemloft.net>

selftests: pmtu.sh: fix result checking

In the PMTU test, when all previous tests are skipped and the new test
passes, the exit code is set to 0. However, the current check mistakenly
treats this as an assignment, causing the check to pass every time.

Consequently, regardless of how many tests have failed, if the latest test
passes, the PMTU test will report a pass.

Fixes: 2a9d3716b810 ("selftests: pmtu.sh: improve the test result processing")
Signed-off-by: Hangbin Liu <liuhangbin@gmail.com>
Acked-by: Po-Hsu Lin <po-hsu.lin@canonical.com>
Signed-off-by: David S. Miller <davem@davemloft.net>

selftests: net: test vxlan pmtu exceptions with tcp

TCP might get stuck if a nonlinear skb exceeds the path MTU,
icmp error contains an incorrect icmp checksum in that case.

Extend the existing test for vxlan to also send at least 1MB worth of
data via TCP in addition to the existing 'large icmp packet adds
route exception'.

On my test VM this fails due to 0-size output file without
"tunnels: fix kasan splat when generating ipv4 pmtu error".

Signed-off-by: Florian Westphal <fw@strlen.de>
Link: https://lore.kernel.org/r/20230803152653.29535-3-fw@strlen.de
Signed-off-by: Jakub Kicinski <kuba@kernel.org>

selftests/net: Find nettest in current directory

The `nettest` binary, built from `selftests/net/nettest.c`,
was expected to be found in the path during test execution of
`fcnal-test.sh` and `pmtu.sh`, leading to tests getting
skipped when the binary is not installed in the system, as can
be seen in these logs found in the wild [1]:

# TEST: vti4: PMTU exceptions [SKIP]
[ 350.600250] IPv6: ADDRCONF(NETDEV_CHANGE): veth_b: link becomes ready
[ 350.607421] IPv6: ADDRCONF(NETDEV_CHANGE): veth_a: link becomes ready
# 'nettest' command not found; skipping tests
# xfrm6udp not supported
# TEST: vti6: PMTU exceptions (ESP-in-UDP) [SKIP]
[ 351.605102] IPv6: ADDRCONF(NETDEV_CHANGE): veth_b: link becomes ready
[ 351.612243] IPv6: ADDRCONF(NETDEV_CHANGE): veth_a: link becomes ready
# 'nettest' command not found; skipping tests
# xfrm4udp not supported

The `unicast_extensions.sh` tests also rely on `nettest`, but
it runs fine there because it looks for the binary in the
current working directory [2]:

The same mechanism that works for the Unicast extensions tests
is here copied over to the PMTU and functional tests.

[1] https://lkft.validation.linaro.org/scheduler/job/5839508#L6221
[2] https://lkft.validation.linaro.org/scheduler/job/5839508#L7958

Signed-off-by: Daniel Díaz <daniel.diaz@linaro.org>
Signed-off-by: David S. Miller <davem@davemloft.net>

selftest: net: Test IPv4 PMTU exceptions with DSCP and ECN

Add two tests to pmtu.sh, for verifying that PMTU exceptions get
properly created for routes that don't belong to the main table.

A fib-rule based on the packet's DSCP field is used to jump to the
correct table. ECN shouldn't interfere with this process, so each test
has two components: one that only sets DSCP and one that sets both DSCP
and ECN.

One of the test triggers PMTU exceptions using ICMP Echo Requests, the
other using UDP packets (to test different handlers in the kernel).

A few adjustments are necessary in the rest of the script to allow
policy routing scenarios:

* Add global variable rt_table that allows setup_routing_*() to
add routes to a specific routing table. By default rt_table is set
to "main", so existing tests don't need to be modified.

* Another global variable, policy_mark, is used to define which
dsfield value is used for policy routing. This variable has no
effect on tests that don't use policy routing.

* The UDP version of the test uses socat. So cleanup() now also need
to kill socat PIDs.

* route_get_dst_pmtu_from_exception() and route_get_dst_exception()
now take an optional third argument specifying the dsfield. If
not specified, 0 is used, so existing users don't need to be
modified.

Signed-off-by: Guillaume Nault <gnault@redhat.com>
Reviewed-by: David Ahern <dsahern@kernel.org>
Signed-off-by: Jakub Kicinski <kuba@kernel.org>

selftests: pmtu.sh: Kill nettest processes launched in subshell.

When using "run_cmd <command> &", then "$!" refers to the PID of the
subshell used to run <command>, not the command itself. Therefore
nettest_pids actually doesn't contain the list of the nettest commands
running in the background. So cleanup() can't kill them and the nettest
processes run until completion (fortunately they have a 5s timeout).

Fix this by defining a new command for running processes in the
background, for which "$!" really refers to the PID of the command run.

Also, double quote variables on the modified lines, to avoid shellcheck
warnings.

Fixes: ece1278a9b81 ("selftests: net: add ESP-in-UDP PMTU test")
Signed-off-by: Guillaume Nault <gnault@redhat.com>
Reviewed-by: Shuah Khan <skhan@linuxfoundation.org>
Signed-off-by: Jakub Kicinski <kuba@kernel.org>

selftests: pmtu.sh: Kill tcpdump processes launched by subshell.

The cleanup() function takes care of killing processes launched by the
test functions. It relies on variables like ${tcpdump_pids} to get the
relevant PIDs. But tests are run in their own subshell, so updated
*_pids values are invisible to other shells. Therefore cleanup() never
sees any process to kill:

$ ./tools/testing/selftests/net/pmtu.sh -t pmtu_ipv4_exception
TEST: ipv4: PMTU exceptions [ OK ]
TEST: ipv4: PMTU exceptions - nexthop objects [ OK ]

$ pgrep -af tcpdump
6084 tcpdump -s 0 -i veth_A-R1 -w pmtu_ipv4_exception_veth_A-R1.pcap
6085 tcpdump -s 0 -i veth_R1-A -w pmtu_ipv4_exception_veth_R1-A.pcap
6086 tcpdump -s 0 -i veth_R1-B -w pmtu_ipv4_exception_veth_R1-B.pcap
6087 tcpdump -s 0 -i veth_B-R1 -w pmtu_ipv4_exception_veth_B-R1.pcap
6088 tcpdump -s 0 -i veth_A-R2 -w pmtu_ipv4_exception_veth_A-R2.pcap
6089 tcpdump -s 0 -i veth_R2-A -w pmtu_ipv4_exception_veth_R2-A.pcap
6090 tcpdump -s 0 -i veth_R2-B -w pmtu_ipv4_exception_veth_R2-B.pcap
6091 tcpdump -s 0 -i veth_B-R2 -w pmtu_ipv4_exception_veth_B-R2.pcap
6228 tcpdump -s 0 -i veth_A-R1 -w pmtu_ipv4_exception_veth_A-R1.pcap
6229 tcpdump -s 0 -i veth_R1-A -w pmtu_ipv4_exception_veth_R1-A.pcap
6230 tcpdump -s 0 -i veth_R1-B -w pmtu_ipv4_exception_veth_R1-B.pcap
6231 tcpdump -s 0 -i veth_B-R1 -w pmtu_ipv4_exception_veth_B-R1.pcap
6232 tcpdump -s 0 -i veth_A-R2 -w pmtu_ipv4_exception_veth_A-R2.pcap
6233 tcpdump -s 0 -i veth_R2-A -w pmtu_ipv4_exception_veth_R2-A.pcap
6234 tcpdump -s 0 -i veth_R2-B -w pmtu_ipv4_exception_veth_R2-B.pcap
6235 tcpdump -s 0 -i veth_B-R2 -w pmtu_ipv4_exception_veth_B-R2.pcap

Fix this by running cleanup() in the context of the test subshell.
Now that each test cleans the environment after completion, there's no
need for calling cleanup() again when the next test starts. So let's
drop it from the setup() function. This is okay because cleanup() is
also called when pmtu.sh starts, so even the first test starts in a
clean environment.

Also, use tcpdump's immediate mode. Otherwise it might not have time to
process buffered packets, resulting in missing packets or even empty
pcap files for short tests.

Note: PAUSE_ON_FAIL is still evaluated before cleanup(), so one can
still inspect the test environment upon failure when using -p.

Fixes: a92a0a7b8e7c ("selftests: pmtu: Simplify cleanup and namespace names")
Signed-off-by: Guillaume Nault <gnault@redhat.com>
Reviewed-by: Shuah Khan <skhan@linuxfoundation.org>
Signed-off-by: Jakub Kicinski <kuba@kernel.org>

selftests: net: add ESP-in-UDP PMTU test

The case of ESP in UDP encapsulation was not covered before. Add
cases of local changes of MTU and difference on routed path.

Signed-off-by: Vadim Fedorenko <vfedorenko@novek.ru>
Signed-off-by: David S. Miller <davem@davemloft.net>

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

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>

selftests: pmtu.sh: improve the test result processing

This test will treat all non-zero return codes as failures, it will
make the pmtu.sh test script being marked as FAILED when some
sub-test got skipped.

Improve the result processing by
* Only mark the whole test script as SKIP when all of the
sub-tests were skipped
* If the sub-tests were either passed or skipped, the overall
result will be PASS
* If any of them has failed with return code 1 or anything bad
happened (e.g. return code 127 for command not found), the
overall result will be FAIL

Signed-off-by: Po-Hsu Lin <po-hsu.lin@canonical.com>
Signed-off-by: Jakub Kicinski <kuba@kernel.org>

selftests: pmtu.sh: use $ksft_skip for skipped return code

This test uses return code 2 as a hard-coded skipped state, let's use
the kselftest framework skip code variable $ksft_skip instead to make
it more readable and easier to maintain.

Signed-off-by: Po-Hsu Lin <po-hsu.lin@canonical.com>
Signed-off-by: Jakub Kicinski <kuba@kernel.org>

selftests: pmtu.sh: Add tests for UDP tunnels handled by Open vSwitch

The new tests check that IP and IPv6 packets exceeding the local PMTU
estimate, forwarded by an Open vSwitch instance from another node,
result in the correct route exceptions being created, and that
communication with end-to-end fragmentation, over GENEVE and VXLAN
Open vSwitch ports, is now possible as a result of PMTU discovery.

Signed-off-by: Stefano Brivio <sbrivio@redhat.com>
Signed-off-by: David S. Miller <davem@davemloft.net>

selftests: pmtu.sh: Add tests for bridged UDP tunnels

The new tests check that IP and IPv6 packets exceeding the local PMTU
estimate, both locally generated and forwarded by a bridge from
another node, result in the correct route exceptions being created,
and that communication with end-to-end fragmentation over VXLAN and
GENEVE tunnels is now possible as a result of PMTU discovery.

Part of the existing setup functions aren't generic enough to simply
add a namespace and a bridge to the existing routing setup. This
rework is in progress and we can easily shrink this once more generic
topology functions are available.

Signed-off-by: Stefano Brivio <sbrivio@redhat.com>
Reviewed-by: David Ahern <dsahern@gmail.com>
Signed-off-by: David S. Miller <davem@davemloft.net>

selftests: pmtu: implement IPIP, SIT and ip6tnl PMTU discovery tests

Add PMTU discovery tests for these encapsulations:

- IPIP
- SIT, mode ip6ip
- ip6tnl, modes ip6ip6 and ipip6

Signed-off-by: Lourdes Pedrajas <lu@pplo.net>
Reviewed-by: Stefano Brivio <sbrivio@redhat.com>
Reviewed-by: David Ahern <dsahern@gmail.com>
Signed-off-by: David S. Miller <davem@davemloft.net>

selftests: pmtu: fix init mtu value in description

There is no a_r3, a_r4 in the testing topology.
It should be b_r1, b_r2. Also b_r1 mtu is 1400 and b_r2 mtu is 1500.

Fixes: e44e428f59e4 ("selftests: pmtu: add basic IPv4 and IPv6 PMTU tests")
Signed-off-by: Hangbin Liu <liuhangbin@gmail.com>
Acked-by: Stefano Brivio <sbrivio@redhat.com>
Signed-off-by: David S. Miller <davem@davemloft.net>

selftests: pmtu: use -oneline for ip route list cache

Some versions of iproute2 will output more than one line per entry, which
will cause the test to fail, like:

TEST: ipv6: list and flush cached exceptions [FAIL]
can't list cached exceptions

That happens, for example, with iproute2 4.15.0. When using the -oneline
option, this will work just fine:

TEST: ipv6: list and flush cached exceptions [ OK ]

This also works just fine with a more recent version of iproute2, like
5.4.0.

For some reason, two lines are printed for the IPv4 test no matter what
version of iproute2 is used. Use the same -oneline parameter there instead
of counting the lines twice.

Fixes: b964641e9925 ("selftests: pmtu: Make list_flush_ipv6_exception test more demanding")
Signed-off-by: Thadeu Lima de Souza Cascardo <cascardo@canonical.com>
Acked-by: Stefano Brivio <sbrivio@redhat.com>
Signed-off-by: David S. Miller <davem@davemloft.net>

selftests: pmtu: Make list_flush_ipv6_exception test more demanding

Instead of just listing and flushing two cached exceptions, create
a relatively big number of them, and count how many are listed. Single
netlink dump messages contain approximately 25 entries each, and this
way we can make sure the partial dump tracking mechanism is working
properly.

While at it, also ensure that no cached routes can be listed after
flush, and remove 'sleep 1' calls, they are not actually needed.

v7: No changes

v6:
- Merge this patch into series including fix, as it's also targeted
for net-next. No actual changes

Signed-off-by: Stefano Brivio <sbrivio@redhat.com>
Signed-off-by: David S. Miller <davem@davemloft.net>

selftests: pmtu: Introduce list_flush_ipv4_exception test case

This test checks that route exceptions can be successfully listed and
flushed using ip -6 route {list,flush} cache.

v7: No changes

v6:
- Merge this patch into series including fix, as it's also targeted
for net-next
- Drop left-over print of 'ip route list cache | wc -l'

Signed-off-by: Stefano Brivio <sbrivio@redhat.com>
Signed-off-by: David S. Miller <davem@davemloft.net>

selftests: pmtu: Introduce list_flush_ipv6_exception test case

This test checks that route exceptions can be successfully listed and
flushed using ip -6 route {list,flush} cache.

Signed-off-by: Stefano Brivio <sbrivio@redhat.com>
Signed-off-by: David S. Miller <davem@davemloft.net>

selftests: pmtu: Add support for routing via nexthop objects

Add routing setup using nexthop objects and repeat tests with
old and new routing.

Signed-off-by: David Ahern <dsahern@gmail.com>
Reviewed-by: Stefano Brivio <sbrivio@redhat.com>
Signed-off-by: David S. Miller <davem@davemloft.net>

selftests: pmtu: Move route installs to a new function

Move the route add commands to a new function called setup_routing_old.
The '_old' refers to the classic way of installing routes.

Signed-off-by: David Ahern <dsahern@gmail.com>
Reviewed-by: Stefano Brivio <sbrivio@redhat.com>
Signed-off-by: David S. Miller <davem@davemloft.net>

selftests: pmtu: Move running of test into a new function

Move the block of code that runs a test and prints the verdict to a
new function, run_test.

Signed-off-by: David Ahern <dsahern@gmail.com>
Reviewed-by: Stefano Brivio <sbrivio@redhat.com>
Signed-off-by: David S. Miller <davem@davemloft.net>

selftests: pmtu: Fix encapsulating device in pmtu_vti6_link_change_mtu

In the pmtu_vti6_link_change_mtu test, both local and remote addresses
for the vti6 tunnel are assigned to the same address given to the dummy
interface that we use as encapsulating device with a known MTU.

This works as long as the dummy interface is actually selected, via
rt6_lookup(), as encapsulating device. But if the remote address of the
tunnel is a local address too, the loopback interface could also be
selected, and there's nothing wrong with it.

This is what some older -stable kernels do (3.18.z, at least), and
nothing prevents us from subtly changing FIB implementation to revert
back to that behaviour in the future.

Define an IPv6 prefix instead, and use two separate addresses as local
and remote for vti6, so that the encapsulating device can't be a
loopback interface.

Reported-by: Xiumei Mu <xmu@redhat.com>
Fixes: 1fad59ea1c34 ("selftests: pmtu: Add pmtu_vti6_link_change_mtu test")
Signed-off-by: Stefano Brivio <sbrivio@redhat.com>
Signed-off-by: David S. Miller <davem@davemloft.net>

selftests: pmtu: Simplify cleanup and namespace names

The point of the pause-on-fail argument is to leave the setup as is after
a test fails to allow a user to debug why it failed. Move the cleanup
after posting the result to the user to make it so.

Random names for the namespaces are not user friendly when trying to
debug a failure. Make them simpler and more direct for the tests. Run
cleanup at the beginning to ensure they are cleaned up if they already
exist.

Remove cleanup_done. There is no harm in doing cleanup twice; just
ignore any errors related to not existing - which is already done.

Signed-off-by: David Ahern <dsahern@gmail.com>
Signed-off-by: David S. Miller <davem@davemloft.net>

selftests: pmtu.sh: Remove quotes around commands in setup_xfrm

The first command in setup_xfrm is failing resulting in the test getting
skipped:

+ ip netns exec ns-B ip -6 xfrm state add src fd00:1::a dst fd00:1::b spi 0x1000 proto esp aead 'rfc4106(gcm(aes))' 0x0f0f0f0f0f0f0f0f0f0f0f0f0f0f0f0f0f0f0f0f 128 mode tunnel
+ out=RTNETLINK answers: Function not implemented
...
xfrm6 not supported
TEST: vti6: PMTU exceptions [SKIP]
xfrm4 not supported
TEST: vti4: PMTU exceptions [SKIP]
...

The setup command started failing when the run_cmd option was added.
Removing the quotes fixes the problem:
...
TEST: vti6: PMTU exceptions [ OK ]
TEST: vti4: PMTU exceptions [ OK ]
...

Fixes: 56490b623aa0 ("selftests: Add debugging options to pmtu.sh")
Signed-off-by: David Ahern <dsahern@gmail.com>
Signed-off-by: David S. Miller <davem@davemloft.net>

selftests: Add debugging options to pmtu.sh

pmtu.sh script runs a number of tests and dumps a summary of pass/fail.
If a test fails, it is near impossible to debug why. For example:

TEST: ipv6: PMTU exceptions [FAIL]

There are a lot of commands run behind the scenes for this test. Which
one is failing?

Add a VERBOSE option to show commands that are run and any output from
those commands. Add a PAUSE_ON_FAIL option to halt the script if a test
fails allowing users to poke around with the setup in the failed state.

In the process, rename tracing to TRACING and move declaration to top
with the new variables.

Signed-off-by: David Ahern <dsahern@gmail.com>
Reviewed-by: Stefano Brivio <sbrivio@redhat.com>
Signed-off-by: David S. Miller <davem@davemloft.net>

selftests: pmtu: add explicit tests for PMTU exceptions cleanup

Add a couple of new tests, explicitly checking that the kernel
timely releases PMTU exceptions on related device removal.
This is mostly a regression test vs the issue fixed by
commit f5b51fe804ec ("ipv6: route: purge exception on removal")

Only 2 new test cases have been added, instead of extending all
the existing ones, because the reproducer requires executing
several commands and would slow down too much the tests otherwise.

v2 -> v3:
- more cleanup, still from Stefano

v1 -> v2:
- several script cleanups, as suggested by Stefano

Signed-off-by: Paolo Abeni <pabeni@redhat.com>
Reviewed-by: David Ahern <dsahern@gmail.com>
Signed-off-by: David S. Miller <davem@davemloft.net>

selftests: pmtu: disable DAD in all namespaces

Otherwise, the configured IPv6 address could be still "tentative"
at test time, possibly causing tests failures.
We can also drop some sleep along the code and decrease the
timeout for most commands so that the test runtime decreases.

v1 -> v2:
- fix comment (Stefano)

Fixes: d1f1b9cbf34c ("selftests: net: Introduce first PMTU test")
Signed-off-by: Paolo Abeni <pabeni@redhat.com>
Reviewed-by: David Ahern <dsahern@gmail.com>
Signed-off-by: David S. Miller <davem@davemloft.net>

selftests: pmtu: Introduce FoU and GUE PMTU exceptions tests

Introduce eight tests, for FoU and GUE, with IPv4 and IPv6 payload,
on IPv4 and IPv6 transport, that check that PMTU exceptions are created
with the right value when exceeding the MTU on a link of the path.

Signed-off-by: Stefano Brivio <sbrivio@redhat.com>
Reviewed-by: Sabrina Dubroca <sd@queasysnail.net>
Signed-off-by: David S. Miller <davem@davemloft.net>

selftests: pmtu: Introduce tests for IPv4/IPv6 over GENEVE over IPv4/IPv6

Use a router between endpoints, implemented via namespaces, set a low MTU
between router and destination endpoint, exceed it and check PMTU value in
route exceptions.

v2:
- Introduce IPv4 tests right away, if iproute2 doesn't support the 'df'
link option they will be skipped (David Ahern)

Signed-off-by: Stefano Brivio <sbrivio@redhat.com>
Reviewed-by: Sabrina Dubroca <sd@queasysnail.net>
Signed-off-by: David S. Miller <davem@davemloft.net>

selftests: pmtu: Introduce tests for IPv4/IPv6 over VXLAN over IPv4/IPv6

Use a router between endpoints, implemented via namespaces, set a low MTU
between router and destination endpoint, exceed it and check PMTU value in
route exceptions.

v2:
- Change all occurrences of VxLAN to VXLAN (Jiri Benc)
- Introduce IPv4 tests right away, if iproute2 doesn't support the 'df'
link option they will be skipped (David Ahern)

Signed-off-by: Stefano Brivio <sbrivio@redhat.com>
Reviewed-by: Sabrina Dubroca <sd@queasysnail.net>
Signed-off-by: David S. Miller <davem@davemloft.net>

selftests: pmtu: Add optional traffic captures for single tests

If --trace is passed as an option and tcpdump is available,
capture traffic for all relevant interfaces to per-test pcap
files named <test>_<interface>.pcap.

Signed-off-by: Stefano Brivio <sbrivio@redhat.com>
Reviewed-by: Sabrina Dubroca <sd@queasysnail.net>
Signed-off-by: David S. Miller <davem@davemloft.net>

selftests: pmtu: Allow selection of single tests

As number of tests is growing, it's quite convenient to allow
single tests to be run.

Display usage when the script is run with any invalid argument,
keep existing semantics when no arguments are passed so that
automated runs won't break.

Instead of just looping on the list of requested tests, if any,
check first that they exist, and go through them in a nested
loop to keep the existing way to display test descriptions.

Signed-off-by: Stefano Brivio <sbrivio@redhat.com>
Reviewed-by: Sabrina Dubroca <sd@queasysnail.net>
Signed-off-by: David S. Miller <davem@davemloft.net>

selftests: pmtu: add basic IPv4 and IPv6 PMTU tests

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.

These new tests use simple routing to exercise the generation and
update of PMTU exceptions in IPv4 and IPv6.

Signed-off-by: Sabrina Dubroca <sd@queasysnail.net>
Signed-off-by: Stefano Brivio <sbrivio@redhat.com>
Reviewed-by: David Ahern <dsahern@gmail.com>
Signed-off-by: David S. Miller <davem@davemloft.net>

selftests: pmtu: extend MTU parsing helper to locked MTU

The 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 <sd@queasysnail.net>
Reviewed-by: David Ahern <dsahern@gmail.com>
Signed-off-by: David S. Miller <davem@davemloft.net>

selftests: pmtu: Introduce check_pmtu_value()

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 <sbrivio@redhat.com>
Signed-off-by: Sabrina Dubroca <sd@queasysnail.net>
Reviewed-by: David Ahern <dsahern@gmail.com>
Signed-off-by: David S. Miller <davem@davemloft.net>

selftests: pmtu: properly redirect stderr to /dev/null

The cleanup function uses "$CMD 2 > /dev/null", which doesn't actually
send stderr to /dev/null, so when the netns doesn't exist, the error
message is shown. Use "2> /dev/null" instead, so that those messages
disappear, as was intended.

Fixes: d1f1b9cbf34c ("selftests: net: Introduce first PMTU test")
Signed-off-by: Sabrina Dubroca <sd@queasysnail.net>
Acked-by: Stefano Brivio <sbrivio@redhat.com>
Signed-off-by: David S. Miller <davem@davemloft.net>

selftests: pmtu: detect correct binary to ping ipv6 addresses

Some systems don't have the ping6 binary anymore, and use ping for
everything. Detect the absence of ping6 and try to use ping instead.

Fixes: d1f1b9cbf34c ("selftests: net: Introduce first PMTU test")
Signed-off-by: Sabrina Dubroca <sd@queasysnail.net>
Acked-by: Stefano Brivio <sbrivio@redhat.com>
Signed-off-by: David S. Miller <davem@davemloft.net>

selftests: pmtu: maximum MTU for vti4 is 2^16-1-20

Since commit 82612de1c98e ("ip_tunnel: restore binding to ifaces with a
large mtu"), the maximum MTU for vti4 is based on IP_MAX_MTU instead of
the mysterious constant 0xFFF8. This makes this selftest fail.

Fixes: 82612de1c98e ("ip_tunnel: restore binding to ifaces with a large mtu")
Signed-off-by: Sabrina Dubroca <sd@queasysnail.net>
Acked-by: Stefano Brivio <sbrivio@redhat.com>
Acked-by: Nicolas Dichtel <nicolas.dichtel@6wind.com>
Signed-off-by: David S. Miller <davem@davemloft.net>

selftests: net: return Kselftest Skip code for skipped tests

When net test is skipped because of unmet dependencies and/or unsupported
configuration, it returns 0 which is treated as a pass by the Kselftest
framework. This leads to false positive result even when the test could
not be run.

Change it to return kselftest skip code when a test gets skipped to
clearly report that the test could not be run.

Kselftest framework SKIP code is 4 and the framework prints appropriate
messages to indicate that the test is skipped.

Change psock_tpacket to use ksft_exit_skip() when a non-root user runs
the test and add an explicit check for root and a clear message, instead
of failing the test when /sys/power/state file open fails.

Signed-off-by: Shuah Khan (Samsung OSG) <shuah@kernel.org>

selftests: pmtu: Minimum MTU for vti6 is 68

A vti6 interface can carry IPv4 packets too.

Signed-off-by: Stefano Brivio <sbrivio@redhat.com>
Reviewed-by: Xin Long <lucien.xin@gmail.com>
Signed-off-by: David S. Miller <davem@davemloft.net>

selftests: pmtu: Drop prints to kernel log from pmtu_vti6_link_change_mtu

Reported-by: David Ahern <dsahern@gmail.com>
Fixes: 1fad59ea1c34 ("selftests: pmtu: Add pmtu_vti6_link_change_mtu test")
Signed-off-by: Stefano Brivio <sbrivio@redhat.com>
Signed-off-by: David S. Miller <davem@davemloft.net>

selftests: pmtu: Add pmtu_vti6_link_change_mtu test

This test checks that MTU configured from userspace is used on
link creation and changes, and that when it's not passed from
userspace, it's calculated properly from the MTU of the lower
layer.

Signed-off-by: Stefano Brivio <sbrivio@redhat.com>
Signed-off-by: David S. Miller <davem@davemloft.net>

selftests: pmtu: Add pmtu_vti6_link_add_mtu test

Same as pmtu_vti4_link_add_mtu test, but for IPv6.

Signed-off-by: Stefano Brivio <sbrivio@redhat.com>
Signed-off-by: David S. Miller <davem@davemloft.net>

selftests: pmtu: Add pmtu_vti4_link_add_mtu test

This test checks that MTU given on vti link creation is actually
configured, and that tunnel is not created with an invalid MTU
value.

Signed-off-by: Stefano Brivio <sbrivio@redhat.com>
Signed-off-by: David S. Miller <davem@davemloft.net>

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>

selftests: pmtu: Add pmtu_vti6_default_mtu test

Same as pmtu_vti4_default_mtu, but on IPv6 with vti6.

Signed-off-by: Stefano Brivio <sbrivio@redhat.com>
Signed-off-by: David S. Miller <davem@davemloft.net>

selftests: pmtu: Add pmtu_vti4_default_mtu test

This test checks that the MTU assigned by default to a vti (IPv4)
interface created on top of veth is simply veth's MTU minus the
length of the encapsulated IPv4 header.

Signed-off-by: Stefano Brivio <sbrivio@redhat.com>
Signed-off-by: David S. Miller <davem@davemloft.net>

selftests: pmtu: Introduce support for multiple tests

Introduce list of tests and their descriptions, and loop on it
in main body.

Tests will now just take care of calling setup with a list of
"units" they need, and return 0 on success, 1 on failure, 2 if
the test had to be skipped.

Main script body will take care of displaying results and
cleaning up after every test. Introduce guard variable so that
we don't clean up twice in case of interrupts or unexpected
failures.

The pmtu_vti6_exception test can now run its third step even if
the previous one failed, as we can return values from it.

Also introduce support to display test descriptions, and display
aligned OK/FAIL/SKIP test outcomes. Buffer error strings so that
in case of failure we can display them right under the outcome
for each test.

Signed-off-by: Stefano Brivio <sbrivio@redhat.com>
Signed-off-by: David S. Miller <davem@davemloft.net>

selftests: pmtu: Factor out MTU parsing helper

...so that it can be used for any iproute command output.

Signed-off-by: Stefano Brivio <sbrivio@redhat.com>
Signed-off-by: David S. Miller <davem@davemloft.net>

selftests: pmtu: Use namespace command prefix to fetch route mtu

In 7af137b72131 ("selftests: net: Introduce first PMTU test") I
accidentally assumed route_get_* helpers would run from a single
namespace. Make them a bit more generic, by passing the
namespace command prefix as a parameter instead.

Fixes: 7af137b72131 ("selftests: net: Introduce first PMTU test")
Signed-off-by: Stefano Brivio <sbrivio@redhat.com>
Signed-off-by: David S. Miller <davem@davemloft.net>

selftests: pmtu: Reverse return codes of functions

David suggests it's more intuitive to return non-zero on
failures, and zero on success.

No need to introduce tail 'return 0' in functions, they will
return the exit code of the last command anyway.

Suggested-by: David Ahern <dsahern@gmail.com>
Signed-off-by: Stefano Brivio <sbrivio@redhat.com>
Signed-off-by: David S. Miller <davem@davemloft.net>

selftests: net: Introduce first PMTU test

One single test implemented so far: test_pmtu_vti6_exception
checks that the PMTU of a route exception, caused by a tunnel
exceeding the link layer MTU, is affected by administrative
changes of the tunnel MTU. Creation of the route exception is
checked too.

Requested-by: David Ahern <dsahern@gmail.com>
Signed-off-by: Stefano Brivio <sbrivio@redhat.com>
Acked-by: David Ahern <dsahern@gmail.com>
Signed-off-by: David S. Miller <davem@davemloft.net>