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a9745a0b68
Work around https://github.com/google/gvisor/issues/5732 by trying to read /proc/net/route with a larger bufsize if it fails the first time. Signed-off-by: Denton Gentry <dgentry@tailscale.com>
87 lines
2.3 KiB
Go
87 lines
2.3 KiB
Go
// Copyright (c) 2021 Tailscale Inc & AUTHORS All rights reserved.
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// Use of this source code is governed by a BSD-style
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// license that can be found in the LICENSE file.
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// +build linux,!redo
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package interfaces
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import (
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"fmt"
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"io/ioutil"
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"os"
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"path/filepath"
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"testing"
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)
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func TestDefaultRouteInterface(t *testing.T) {
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// tests /proc/net/route on the local system, cannot make an assertion about
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// the correct interface name, but good as a sanity check.
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v, err := DefaultRouteInterface()
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if err != nil {
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t.Fatal(err)
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}
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t.Logf("got %q", v)
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}
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// test the specific /proc/net/route path as found on Google Cloud Run instances
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func TestGoogleCloudRunDefaultRouteInterface(t *testing.T) {
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dir := t.TempDir()
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savedProcNetRoutePath := procNetRoutePath
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defer func() { procNetRoutePath = savedProcNetRoutePath }()
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procNetRoutePath = filepath.Join(dir, "CloudRun")
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buf := []byte("Iface\tDestination\tGateway\tFlags\tRefCnt\tUse\tMetric\tMask\tMTU\tWindow\tIRTT\n" +
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"eth0\t8008FEA9\t00000000\t0001\t0\t0\t0\t01FFFFFF\t0\t0\t0\n" +
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"eth1\t00000000\t00000000\t0001\t0\t0\t0\t00000000\t0\t0\t0\n")
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err := ioutil.WriteFile(procNetRoutePath, buf, 0644)
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if err != nil {
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t.Fatal(err)
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}
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got, err := DefaultRouteInterface()
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if err != nil {
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t.Fatal(err)
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}
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if got != "eth1" {
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t.Fatalf("got %s, want eth1", got)
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}
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}
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// we read chunks of /proc/net/route at a time, test that files longer than the chunk
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// size can be handled.
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func TestExtremelyLongProcNetRoute(t *testing.T) {
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dir := t.TempDir()
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savedProcNetRoutePath := procNetRoutePath
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defer func() { procNetRoutePath = savedProcNetRoutePath }()
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procNetRoutePath = filepath.Join(dir, "VeryLong")
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f, err := os.Create(procNetRoutePath)
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if err != nil {
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t.Fatal(err)
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}
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_, err = f.Write([]byte("Iface\tDestination\tGateway\tFlags\tRefCnt\tUse\tMetric\tMask\tMTU\tWindow\tIRTT\n"))
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if err != nil {
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t.Fatal(err)
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}
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for n := 0; n <= 1000; n++ {
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line := fmt.Sprintf("eth%d\t8008FEA9\t00000000\t0001\t0\t0\t0\t01FFFFFF\t0\t0\t0\n", n)
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_, err := f.Write([]byte(line))
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if err != nil {
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t.Fatal(err)
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}
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}
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_, err = f.Write([]byte("tokenring1\t00000000\t00000000\t0001\t0\t0\t0\t00000000\t0\t0\t0\n"))
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if err != nil {
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t.Fatal(err)
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}
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got, err := DefaultRouteInterface()
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if err != nil {
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t.Fatal(err)
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}
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if got != "tokenring1" {
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t.Fatalf("got %q, want tokenring1", got)
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}
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}
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