85 lines
2.8 KiB
Go
85 lines
2.8 KiB
Go
// Copyright 2020 The gVisor Authors.
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//
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// Licensed under the Apache License, Version 2.0 (the "License");
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// you may not use this file except in compliance with the License.
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// You may obtain a copy of the License at
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//
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// http://www.apache.org/licenses/LICENSE-2.0
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//
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// Unless required by applicable law or agreed to in writing, software
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// distributed under the License is distributed on an "AS IS" BASIS,
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// WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
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// See the License for the specific language governing permissions and
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// limitations under the License.
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package tcp_retransmits_test
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import (
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"flag"
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"testing"
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"time"
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"golang.org/x/sys/unix"
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"gvisor.dev/gvisor/pkg/tcpip/header"
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"gvisor.dev/gvisor/test/packetimpact/testbench"
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)
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func init() {
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testbench.RegisterFlags(flag.CommandLine)
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}
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// TestRetransmits tests retransmits occur at exponentially increasing
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// time intervals.
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func TestRetransmits(t *testing.T) {
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dut := testbench.NewDUT(t)
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defer dut.TearDown()
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listenFd, remotePort := dut.CreateListener(t, unix.SOCK_STREAM, unix.IPPROTO_TCP, 1)
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defer dut.Close(t, listenFd)
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conn := testbench.NewTCPIPv4(t, testbench.TCP{DstPort: &remotePort}, testbench.TCP{SrcPort: &remotePort})
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defer conn.Close(t)
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conn.Connect(t)
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acceptFd, _ := dut.Accept(t, listenFd)
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defer dut.Close(t, acceptFd)
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dut.SetSockOptInt(t, acceptFd, unix.IPPROTO_TCP, unix.TCP_NODELAY, 1)
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sampleData := []byte("Sample Data")
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samplePayload := &testbench.Payload{Bytes: sampleData}
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dut.Send(t, acceptFd, sampleData, 0)
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if _, err := conn.ExpectData(t, &testbench.TCP{}, samplePayload, time.Second); err != nil {
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t.Fatalf("expected payload was not received: %s", err)
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}
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// Give a chance for the dut to estimate RTO with RTT from the DATA-ACK.
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// TODO(gvisor.dev/issue/2685) Estimate RTO during handshake, after which
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// we can skip sending this ACK.
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conn.Send(t, testbench.TCP{Flags: testbench.Uint8(header.TCPFlagAck)})
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startRTO := time.Second
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current := startRTO
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first := time.Now()
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dut.Send(t, acceptFd, sampleData, 0)
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seq := testbench.Uint32(uint32(*conn.RemoteSeqNum(t)))
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if _, err := conn.ExpectData(t, &testbench.TCP{SeqNum: seq}, samplePayload, startRTO); err != nil {
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t.Fatalf("expected payload was not received: %s", err)
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}
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// Expect retransmits of the same segment.
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for i := 0; i < 5; i++ {
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start := time.Now()
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if _, err := conn.ExpectData(t, &testbench.TCP{SeqNum: seq}, samplePayload, 2*current); err != nil {
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t.Fatalf("expected payload was not received: %s loop %d", err, i)
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}
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if i == 0 {
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startRTO = time.Now().Sub(first)
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current = 2 * startRTO
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continue
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}
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// Check if the probes came at exponentially increasing intervals.
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if p := time.Since(start); p < current-startRTO {
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t.Fatalf("retransmit came sooner interval %d probe %d", p, i)
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}
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current *= 2
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}
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}
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