EbpfTracker refactoring / cleanup #2699
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2opremio
reviewed
Jul 11, 2017
probe/endpoint/connection_tracker.go
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| func (t *connectionTracker) existingFlows() map[string]fourTuple { | ||
| seenTuples := map[string]fourTuple{} | ||
| if !t.conf.UseConntrack { | ||
| log.Warnf("Not using conntrack: disabled") |
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2opremio
approved these changes
Jul 11, 2017
premature abstraction
when we got an fd install event but the pid was dead by time we processed it, we would fail to remove the watcher for that pid from the fdinstall_pids table. This is a minor, and bounded, leak, since the table only contains pids that were alive when we initialized ebpf. And this change only plugs that leak very partially, since we will never remove pids that die while sitting in accept().
which presumably could cause havoc
We were enabling event processing before feeding in the initial connections, which results in a non-deterministic outcome.
Without synchronisation, the isDead() call might return a stale value, delaying deadness detection potentially indefinitely. Without the guards / idempotence in .stop(), invoking stop() more than once could cause a panic, since tracer.Stop() closes a channel (which panics on a closed channel). Multiple stop() invocations are rare, but not impossible.
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a bunch of refactors, and race condition fixes.
Best reviewed commit-by-commit.