65 lines
1.1 KiB
Go
65 lines
1.1 KiB
Go
// Copyright (c) Tailscale Inc & AUTHORS
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// SPDX-License-Identifier: BSD-3-Clause
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package tcpinfo
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import (
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"bytes"
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"io"
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"net"
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"runtime"
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"testing"
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)
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func TestRTT(t *testing.T) {
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switch runtime.GOOS {
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case "linux", "darwin":
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default:
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t.Skipf("not currently supported on %s", runtime.GOOS)
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}
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ln, err := net.Listen("tcp4", "localhost:0")
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if err != nil {
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t.Fatal(err)
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}
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defer ln.Close()
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go func() {
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for {
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c, err := ln.Accept()
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if err != nil {
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return
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}
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t.Cleanup(func() { c.Close() })
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// Copy from the client to nowhere
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go io.Copy(io.Discard, c)
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}
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}()
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conn, err := net.Dial("tcp4", ln.Addr().String())
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if err != nil {
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t.Fatal(err)
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}
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// Write a bunch of data to the conn to force TCP session establishment
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// and a few packets.
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junkData := bytes.Repeat([]byte("hello world\n"), 1024*1024)
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for i := 0; i < 10; i++ {
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if _, err := conn.Write(junkData); err != nil {
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t.Fatalf("error writing junk data [%d]: %v", i, err)
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}
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}
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// Get the RTT now
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rtt, err := RTT(conn)
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if err != nil {
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t.Fatalf("error getting RTT: %v", err)
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}
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if rtt == 0 {
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t.Errorf("expected RTT > 0")
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}
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t.Logf("TCP rtt: %v", rtt)
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}
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