Run ip neigh flush before removing the IP address from the interface#3281
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saiarcot895 merged 2 commits intosonic-net:masterfrom Apr 29, 2024
Merged
Run ip neigh flush before removing the IP address from the interface#3281saiarcot895 merged 2 commits intosonic-net:masterfrom
ip neigh flush before removing the IP address from the interface#3281saiarcot895 merged 2 commits intosonic-net:masterfrom
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In the test_po_update test case, one of the things done there is to remove an IP address from a port channel interface. As part of that, the current handling for that issues a `ip neigh flush dev ...` command, added in sonic-net#606, presumably to remove old neighbor entries that would no longer be valid. I would think that the kernel would automatically do this, but maybe it didn't back then; I'm not sure if there's been a behavior change here since then. In some cases, this command is returning an error, saying "Failed to send flush request: No such file or directory". I'm not sure why this is; maybe when iproute2 is going through the list of neighbors, some neighbor entry was there, but then by the time it issued the deletion request, that neighbor entry was removed by the kernel since the IP address was removed. Either way, I don't believe a failure here is critical. Therefore, ignore any failures from running this command. Signed-off-by: Saikrishna Arcot <[email protected]>
prsunny
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Apr 22, 2024
This should make sure that the IP neighbor flush should always work. This also requires the tests to be updated, to mock out the flush command call since that interface won't exist. Signed-off-by: Saikrishna Arcot <[email protected]>
saiarcot895
changed the title
ip neigh fluship neigh flush before removing the IP address from the interface
prsunny
approved these changes
Apr 29, 2024
arfeigin
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Jun 16, 2024
sonic-net#3281) * Ignore any error returned from `ip neigh flush` In the test_po_update test case, one of the things done there is to remove an IP address from a port channel interface. As part of that, the current handling for that issues a `ip neigh flush dev ...` command, added in sonic-net#606, presumably to remove old neighbor entries that would no longer be valid. I would think that the kernel would automatically do this, but maybe it didn't back then; I'm not sure if there's been a behavior change here since then. In some cases, this command is returning an error, saying "Failed to send flush request: No such file or directory". I'm not sure why this is; maybe when iproute2 is going through the list of neighbors, some neighbor entry was there, but then by the time it issued the deletion request, that neighbor entry was removed by the kernel since the IP address was removed. Either way, I don't believe a failure here is critical. Therefore, ignore any failures from running this command. Signed-off-by: Saikrishna Arcot <[email protected]> * Move the IP neighbor flush to be before the IP address removal This should make sure that the IP neighbor flush should always work. This also requires the tests to be updated, to mock out the flush command call since that interface won't exist. Signed-off-by: Saikrishna Arcot <[email protected]> --------- Signed-off-by: Saikrishna Arcot <[email protected]>
nmoray
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Jun 25, 2025
sonic-net#3281) * Ignore any error returned from `ip neigh flush` In the test_po_update test case, one of the things done there is to remove an IP address from a port channel interface. As part of that, the current handling for that issues a `ip neigh flush dev ...` command, added in sonic-net#606, presumably to remove old neighbor entries that would no longer be valid. I would think that the kernel would automatically do this, but maybe it didn't back then; I'm not sure if there's been a behavior change here since then. In some cases, this command is returning an error, saying "Failed to send flush request: No such file or directory". I'm not sure why this is; maybe when iproute2 is going through the list of neighbors, some neighbor entry was there, but then by the time it issued the deletion request, that neighbor entry was removed by the kernel since the IP address was removed. Either way, I don't believe a failure here is critical. Therefore, ignore any failures from running this command. Signed-off-by: Saikrishna Arcot <[email protected]> * Move the IP neighbor flush to be before the IP address removal This should make sure that the IP neighbor flush should always work. This also requires the tests to be updated, to mock out the flush command call since that interface won't exist. Signed-off-by: Saikrishna Arcot <[email protected]> --------- Signed-off-by: Saikrishna Arcot <[email protected]>
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What I did
In the test_po_update test case, one of the things done there is to remove an IP address from a port channel interface. As part of that, the current handling for that issues a
ip neigh flush dev ...command, added in #606, presumably to remove old neighbor entries that would no longer be valid. I would think that the kernel would automatically do this, but maybe it didn't back then; I'm not sure if there's been a behavior change here since then.In some cases, this command is returning an error, saying "Failed to send flush request: No such file or directory". I'm not sure why this is; maybe when iproute2 is going through the list of neighbors, some neighbor entry was there, but then by the time it issued the deletion request, that neighbor entry was removed by the kernel since the IP address was removed. Either way, I don't believe a failure here is critical.
To get around this, run the
ip neigh flushcommand before removing the IP address from the interface. This should make sure it succeeds. Also, update the test cases to mock out this call (so that it doesn't return an error here and bail early) and update the exit code.How I did it
How to verify it
The
ip neigh flushfailure appears to be flaky, but I've seen a small uptick in those failures recently. I haven't been able to repro the error on my dev VM, so I'm not sure if this is a good enough fix if it does run into the failure case.Previous command output (if the output of a command-line utility has changed)
New command output (if the output of a command-line utility has changed)