kernel/tools/testing/selftests/net/pmtu.sh, branch linux-rolling-stable

selftests: net: speed up pmtu.sh by avoiding unnecessary cleanup

2025-09-09T23:26:44Z

The pmtu test takes nearly an hour when run on a debug kernel (10min on a normal kernel, so the debug slow down is quite significant). NIPA tries to ensure all results are delivered by a certain deadline so this prevents it from retrying the test in case of a flake. Looks like one of the slowest operations in the test is calling out to ./openvswitch/ovs-dpctl.py to remove potential leftover OvS interfaces. Check whether the interfaces exist in the first place in sysfs, since it can be done directly in bash it is very fast. This should save us around 20-30% of the test runtime. Reviewed-by: Simon Horman Link: https://patch.msgid.link/20250906214535.3204785-1-kuba@kernel.org Signed-off-by: Jakub Kicinski

selftests: net: move wait_local_port_listen to lib.sh

2025-05-28T00:31:42Z

The function wait_local_port_listen() is the only function defined in net_helper.sh. Since some tests source both lib.sh and net_helper.sh, we can simplify the setup by moving wait_local_port_listen() to lib.sh. With this change, net_helper.sh becomes redundant and can be removed. Signed-off-by: Hangbin Liu Reviewed-by: Matthieu Baerts (NGI0) Link: https://patch.msgid.link/20250526014600.9128-1-liuhangbin@gmail.com Signed-off-by: Jakub Kicinski

net: ipv4: Cache pmtu for all packet paths if multipath enabled

2024-11-12T03:07:36Z

Check number of paths by fib_info_num_path(), and update_or_create_fnhe() for every path. Problem is that pmtu is cached only for the oif that has received icmp message "need to frag", other oifs will still try to use "default" iface mtu. An example topology showing the problem: | host1 +---------+ | dummy0 | 10.179.20.18/32 mtu9000 +---------+ +-----------+----------------+ +---------+ +---------+ | ens17f0 | 10.179.2.141/31 | ens17f1 | 10.179.2.13/31 +---------+ +---------+ | (all here have mtu 9000) | +------+ +------+ | ro1 | 10.179.2.140/31 | ro2 | 10.179.2.12/31 +------+ +------+ | | ---------+------------+-------------------+------ | +-----+ | ro3 | 10.10.10.10 mtu1500 +-----+ | ======================================== some networks ======================================== | +-----+ | eth0| 10.10.30.30 mtu9000 +-----+ | host2 host1 have enabled multipath and sysctl net.ipv4.fib_multipath_hash_policy = 1: default proto static src 10.179.20.18 nexthop via 10.179.2.12 dev ens17f1 weight 1 nexthop via 10.179.2.140 dev ens17f0 weight 1 When host1 tries to do pmtud from 10.179.20.18/32 to host2, host1 receives at ens17f1 iface an icmp packet from ro3 that ro3 mtu=1500. And host1 caches it in nexthop exceptions cache. Problem is that it is cached only for the iface that has received icmp, and there is no way that ro3 will send icmp msg to host1 via another path. Host1 now have this routes to host2: ip r g 10.10.30.30 sport 30000 dport 443 10.10.30.30 via 10.179.2.12 dev ens17f1 src 10.179.20.18 uid 0 cache expires 521sec mtu 1500 ip r g 10.10.30.30 sport 30033 dport 443 10.10.30.30 via 10.179.2.140 dev ens17f0 src 10.179.20.18 uid 0 cache So when host1 tries again to reach host2 with mtu>1500, if packet flow is lucky enough to be hashed with oif=ens17f1 its ok, if oif=ens17f0 it blackholes and still gets icmp msgs from ro3 to ens17f1, until lucky day when ro3 will send it through another flow to ens17f0. Signed-off-by: Vladimir Vdovin Reviewed-by: Ido Schimmel Link: https://patch.msgid.link/20241108093427.317942-1-deliran@verdict.gg Signed-off-by: Jakub Kicinski

selftests: net: really check for bg process completion

2024-11-07T01:27:35Z

A recent refactor transformed the check for process completion in a true statement, due to a typo. As a result, the relevant test-case is unable to catch the regression it was supposed to detect. Restore the correct condition. Fixes: 691bb4e49c98 ("selftests: net: avoid just another constant wait") Signed-off-by: Paolo Abeni Reviewed-by: David Ahern Link: https://patch.msgid.link/0e6f213811f8e93a235307e683af8225cc6277ae.1730828007.git.pabeni@redhat.com Signed-off-by: Jakub Kicinski

selftests: net: add helper for checking if nettest is available

2024-08-22T10:55:47Z

A few tests check if nettest exists in the $PATH before adding $PWD to $PATH and re-checking. They don't discard stderr on the first check (and nettest is built as part of selftests, so it's pretty normal for it to not be available in system $PATH). This leads to output noise: which: no nettest in (/home/virtme/tools/fs/bin:/home/virtme/tools/fs/sbin:/home/virtme/tools/fs/usr/bin:/home/virtme/tools/fs/usr/sbin:/bin:/sbin:/usr/bin:/usr/sbin:/usr/local/bin) Add a common helper for the check which does silence stderr. There is another small functional change hiding here, because pmtu.sh and fib_rule_tests.sh used to return from the test case rather than completely exit. Building nettest is not hard, there should be no need to maintain the ability to selectively skip cases in its absence. Reviewed-by: Ido Schimmel Signed-off-by: Jakub Kicinski Reviewed-by: Hangbin Liu Link: https://patch.msgid.link/20240821012227.1398769-1-kuba@kernel.org Signed-off-by: Paolo Abeni

selftests/net/pmtu.sh: Fix typo in error message

2024-08-16T00:38:40Z

The word 'expected' was spelled as 'exepcted'. Fixed the typo in this patch. Signed-off-by: Abhash Jha Reviewed-by: Simon Horman Link: https://patch.msgid.link/20240814173121.33590-1-abhashkumarjha123@gmail.com Signed-off-by: Jakub Kicinski

selftests: net: Use the provided dpctl rather than the vswitchd for tests.

2024-06-27T22:44:07Z

The current pmtu test infrastucture requires an installed copy of the ovs-vswitchd userspace. This means that any automated or constrained environments may not have the requisite tools to run the tests. However, the pmtu tests don't require any special classifier processing. Indeed they are only using the vswitchd in the most basic mode - as a NORMAL switch. However, the ovs-dpctl kernel utility can now program all the needed basic flows to allow traffic to traverse the tunnels and provide support for at least testing some basic pmtu scenarios. More complicated flow pipelines can be added to the internal ovs test infrastructure, but that is work for the future. For now, enable the most common cases - wide mega flows with no other prerequisites. Enhance the pmtu testing to try testing using the internal utility, first. As a fallback, if the internal utility isn't running, then try with the ovs-vswitchd userspace tools. Additionally, make sure that when the pyroute2 package is not available the ovs-dpctl utility will error out to properly signal an error has occurred and skip using the internal utility. Reviewed-by: Stefano Brivio Signed-off-by: Aaron Conole Reviewed-by: Simon Horman Tested-by: Simon Horman Link: https://patch.msgid.link/20240625172245.233874-7-aconole@redhat.com Signed-off-by: Jakub Kicinski

selftests: net: more pmtu.sh fixes

2024-02-13T18:19:05Z

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 Link: https://lore.kernel.org/r/4f51c11a1ce7ca7a4dabd926cffff63dadac9ba1.1707731086.git.pabeni@redhat.com Signed-off-by: Jakub Kicinski

selftests: net: avoid just another constant wait

2024-02-03T05:11:21Z

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 Reviewed-by: David Ahern Link: https://lore.kernel.org/r/fd5c745e9bb665b724473af6a9373a8c2a62b247.1706812005.git.pabeni@redhat.com Signed-off-by: Jakub Kicinski

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

2024-02-03T05:11:21Z

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 Reviewed-by: David Ahern Link: https://lore.kernel.org/r/f8e8f6d44427d8c45e9f6a71ee1a321047452087.1706812005.git.pabeni@redhat.com Signed-off-by: Jakub Kicinski