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rtnl: improve event reception in order to avoid ENOBUFS #185

Merged
merged 3 commits into from
Jan 11, 2024
Merged

rtnl: improve event reception in order to avoid ENOBUFS #185

merged 3 commits into from
Jan 11, 2024

Commits on Jan 10, 2024

  1. rtnl: store callback in listener registry only on success 

    Only store the callback reference in the registry once the listener
context was successfully initialized, to avoid keeping a lingering
entry when invalid parameters are passed.

Signed-off-by: Jo-Philipp Wich <jo@mein.io>
    @jow-
    jow- committed Jan 10, 2024
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  2. rtnl: optimize reception of rtnl events 

    Once we're notified about pending data on the netlink event socket,
try to receive as much messages as possible in order to empty the socket
buffer. In contrast to the previous implementation which received one
message per epoll read notification, this avoids some premature ENOBUFS
situations when a huge burst of messages arrives, e.g. due to kernel
side GC runs on the neighbor table.

Since libnl's nl_recvmsgs*() functions do not expose the underlying
-1 error returned by the recvmsg() calls, we need to indirectly check
for errors through errno variable, so clear it out both before the
recvmsgs() call and after successfully completing a message reception
callback invocation.

Signed-off-by: Jo-Philipp Wich <jo@mein.io>
    @jow-
    jow- committed Jan 10, 2024
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  3. rtnl: increase event socket rx buffer size limit to 1 MiB 

    Use the same RX buffer size which iproute2 uses as default, in order to
avoid (or rather, delay as much as possible) ENOBUFS conditions when
receiving a large burst of netlink notifications.

Signed-off-by: Jo-Philipp Wich <jo@mein.io>
    @jow-
    jow- committed Jan 10, 2024
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