mirror of
https://github.com/tailscale/tailscale.git
synced 2025-11-03 17:51:28 +01:00
71029cea2d
This updates all source files to use a new standard header for copyright and license declaration. Notably, copyright no longer includes a date, and we now use the standard SPDX-License-Identifier header. This commit was done almost entirely mechanically with perl, and then some minimal manual fixes. Updates #6865 Signed-off-by: Will Norris <will@tailscale.com>
55 lines
1006 B
Go
55 lines
1006 B
Go
// Copyright (c) Tailscale Inc & AUTHORS
|
|
// SPDX-License-Identifier: BSD-3-Clause
|
|
|
|
//go:build ignore
|
|
|
|
// Command dns_tester exists in order to perform tests of our DNS
|
|
// configuration stack. This was written because the state of DNS
|
|
// in our target environments is so diverse that we need a little tool
|
|
// to do this test for us.
|
|
package main
|
|
|
|
import (
|
|
"context"
|
|
"encoding/json"
|
|
"flag"
|
|
"net"
|
|
"os"
|
|
"time"
|
|
)
|
|
|
|
func main() {
|
|
flag.Parse()
|
|
target := flag.Arg(0)
|
|
|
|
ctx, cancel := context.WithCancel(context.Background())
|
|
defer cancel()
|
|
|
|
errCount := 0
|
|
wait := 25 * time.Millisecond
|
|
for range make([]struct{}, 5) {
|
|
err := lookup(ctx, target)
|
|
if err != nil {
|
|
errCount++
|
|
time.Sleep(wait)
|
|
wait = wait * 2
|
|
continue
|
|
}
|
|
|
|
break
|
|
}
|
|
}
|
|
|
|
func lookup(ctx context.Context, target string) error {
|
|
ctx, cancel := context.WithTimeout(ctx, time.Second)
|
|
defer cancel()
|
|
|
|
hosts, err := net.LookupHost(target)
|
|
if err != nil {
|
|
return err
|
|
}
|
|
|
|
json.NewEncoder(os.Stdout).Encode(hosts)
|
|
return nil
|
|
}
|