Jonathan Nobels
3e89068792
updates tailscale/corp#33891 Addresses several older the TODO's in netmon. This removes the Major flag precomputes the ChangeDelta state, rather than making consumers of ChangeDeltas sort that out themselves. We're also seeing a lot of ChangeDelta's being flagged as "Major" when they are not interesting, triggering rebinds in wgengine that are not needed. This cleans that up and adds a host of additional tests. The dependencies are cleaned, notably removing dependency on netmon itself for calculating what is interesting, and what is not. This includes letting individual platforms set a bespoke global "IsInterestingInterface" function. This is only used on Darwin. RebindRequired now roughly follows how "Major" was historically calculated but includes some additional checks for various uninteresting events such as changes in interface addresses that shouldn't trigger a rebind. This significantly reduces thrashing (by roughly half on Darwin clients which switching between nics). The individual values that we roll into RebindRequired are also exposed so that components consuming netmap.ChangeDelta can ask more targeted questions. Signed-off-by: Jonathan Nobels <jonathan@tailscale.com>
94 lines
2.4 KiB
Go
94 lines
2.4 KiB
Go
// Copyright (c) Tailscale Inc & AUTHORS
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// SPDX-License-Identifier: BSD-3-Clause
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package netmon
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import (
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"bytes"
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"context"
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"fmt"
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"testing"
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"testing/synctest"
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"tailscale.com/util/eventbus"
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"tailscale.com/util/eventbus/eventbustest"
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)
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func TestLinkChangeLogLimiter(t *testing.T) { synctest.Test(t, syncTestLinkChangeLogLimiter) }
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func syncTestLinkChangeLogLimiter(t *testing.T) {
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bus := eventbus.New()
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defer bus.Close()
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mon, err := New(bus, t.Logf)
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if err != nil {
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t.Fatal(err)
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}
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defer mon.Close()
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var logBuffer bytes.Buffer
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logf := func(format string, args ...any) {
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t.Logf("captured log: "+format, args...)
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if format[len(format)-1] != '\n' {
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format += "\n"
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}
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fmt.Fprintf(&logBuffer, format, args...)
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}
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ctx, cancel := context.WithCancel(t.Context())
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defer cancel()
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logf = LinkChangeLogLimiter(ctx, logf, mon)
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// Log once, which should write to our log buffer.
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logf("hello %s", "world")
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if got := logBuffer.String(); got != "hello world\n" {
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t.Errorf("unexpected log buffer contents: %q", got)
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}
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// Log again, which should not write to our log buffer.
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logf("hello %s", "andrew")
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if got := logBuffer.String(); got != "hello world\n" {
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t.Errorf("unexpected log buffer contents: %q", got)
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}
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// Log a different message, which should write to our log buffer.
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logf("other message")
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if got := logBuffer.String(); got != "hello world\nother message\n" {
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t.Errorf("unexpected log buffer contents: %q", got)
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}
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// Synthesize a fake major change event, which should clear the format
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// string cache and allow the next log to write to our log buffer.
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//
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// InjectEvent doesn't work because it's not a major event, so we
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// instead inject the event ourselves.
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injector := eventbustest.NewInjector(t, bus)
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cd, err := NewChangeDelta(nil, &State{}, true, "tailscale0", true)
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if err != nil {
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t.Fatal(err)
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}
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if cd.RebindLikelyRequired != true {
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t.Fatalf("expected RebindLikelyRequired to be true, got false")
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}
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eventbustest.Inject(injector, cd)
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synctest.Wait()
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logf("hello %s", "world")
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want := "hello world\nother message\nhello world\n"
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if got := logBuffer.String(); got != want {
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t.Errorf("unexpected log buffer contents, got: %q, want, %q", got, want)
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}
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// Canceling the context we passed to LinkChangeLogLimiter should
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// unregister the callback from the netmon.
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cancel()
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synctest.Wait()
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mon.mu.Lock()
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if len(mon.cbs) != 0 {
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t.Errorf("expected no callbacks, got %v", mon.cbs)
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}
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mon.mu.Unlock()
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}
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