gvisor.dev/gvisor@v0.0.0-20240520182842-f9d4d51c7e0f/test/packetimpact/tests/tcp_info_test.go (about)

     1  // Copyright 2020 The gVisor Authors.
     2  //
     3  // Licensed under the Apache License, Version 2.0 (the "License");
     4  // you may not use this file except in compliance with the License.
     5  // You may obtain a copy of the License at
     6  //
     7  //     http://www.apache.org/licenses/LICENSE-2.0
     8  //
     9  // Unless required by applicable law or agreed to in writing, software
    10  // distributed under the License is distributed on an "AS IS" BASIS,
    11  // WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
    12  // See the License for the specific language governing permissions and
    13  // limitations under the License.
    14  
    15  package tcp_info_test
    16  
    17  import (
    18  	"flag"
    19  	"testing"
    20  	"time"
    21  
    22  	"golang.org/x/sys/unix"
    23  	"gvisor.dev/gvisor/pkg/abi/linux"
    24  	"gvisor.dev/gvisor/pkg/tcpip/header"
    25  	"gvisor.dev/gvisor/test/packetimpact/testbench"
    26  )
    27  
    28  func init() {
    29  	testbench.Initialize(flag.CommandLine)
    30  }
    31  
    32  func TestTCPInfo(t *testing.T) {
    33  	// Create a socket, listen, TCP connect, and accept.
    34  	dut := testbench.NewDUT(t)
    35  	listenFD, remotePort := dut.CreateListener(t, unix.SOCK_STREAM, unix.IPPROTO_TCP, 1)
    36  	defer dut.Close(t, listenFD)
    37  
    38  	conn := dut.Net.NewTCPIPv4(t, testbench.TCP{DstPort: &remotePort}, testbench.TCP{SrcPort: &remotePort})
    39  	defer conn.Close(t)
    40  	conn.Connect(t)
    41  
    42  	acceptFD, _ := dut.Accept(t, listenFD)
    43  	defer dut.Close(t, acceptFD)
    44  
    45  	// Send and receive sample data.
    46  	sampleData := []byte("Sample Data")
    47  	samplePayload := &testbench.Payload{Bytes: sampleData}
    48  	dut.Send(t, acceptFD, sampleData, 0)
    49  	if _, err := conn.ExpectData(t, &testbench.TCP{}, samplePayload, time.Second); err != nil {
    50  		t.Fatalf("expected a packet with payload %s: %s", samplePayload, err)
    51  	}
    52  	conn.Send(t, testbench.TCP{Flags: testbench.TCPFlags(header.TCPFlagAck)})
    53  
    54  	info := dut.GetSockOptTCPInfo(t, acceptFD)
    55  	if got, want := uint32(info.State), linux.TCP_ESTABLISHED; got != want {
    56  		t.Fatalf("got %d want %d", got, want)
    57  	}
    58  	if info.RTT == 0 {
    59  		t.Errorf("got RTT=0, want nonzero")
    60  	}
    61  	if info.RTTVar == 0 {
    62  		t.Errorf("got RTTVar=0, want nonzero")
    63  	}
    64  	if info.RTO == 0 {
    65  		t.Errorf("got RTO=0, want nonzero")
    66  	}
    67  	if info.ReordSeen != 0 {
    68  		t.Errorf("expected the connection to not have any reordering, got: %d want: 0", info.ReordSeen)
    69  	}
    70  	if info.SndCwnd == 0 {
    71  		t.Errorf("expected send congestion window to be greater than zero")
    72  	}
    73  	if info.CaState != linux.TCP_CA_Open {
    74  		t.Errorf("expected the connection to be in open state, got: %d want: %d", info.CaState, linux.TCP_CA_Open)
    75  	}
    76  
    77  	if t.Failed() {
    78  		t.FailNow()
    79  	}
    80  
    81  	// Check the congestion control state and send congestion window after
    82  	// retransmission timeout.
    83  	seq := testbench.Uint32(uint32(*conn.RemoteSeqNum(t)))
    84  	dut.Send(t, acceptFD, sampleData, 0)
    85  	if _, err := conn.ExpectData(t, &testbench.TCP{}, samplePayload, time.Second); err != nil {
    86  		t.Fatalf("expected a packet with payload %s: %s", samplePayload, err)
    87  	}
    88  
    89  	// Given a generous retransmission timeout.
    90  	timeout := time.Duration(info.RTO) * 2 * time.Microsecond
    91  	if _, err := conn.ExpectData(t, &testbench.TCP{SeqNum: seq}, samplePayload, timeout); err != nil {
    92  		t.Fatalf("expected a packet with payload %s: %s", samplePayload, err)
    93  	}
    94  
    95  	info = dut.GetSockOptTCPInfo(t, acceptFD)
    96  	if info.CaState != linux.TCP_CA_Loss {
    97  		t.Errorf("expected the connection to be in loss recovery, got: %d want: %d", info.CaState, linux.TCP_CA_Loss)
    98  	}
    99  	if info.SndCwnd != 1 {
   100  		t.Errorf("expected send congestion window to be 1, got: %d", info.SndCwnd)
   101  	}
   102  }