// Copyright 2018 Google LLC
//
// Licensed under the Apache License, Version 2.0 (the "License");
// you may not use this file except in compliance with the License.
// You may obtain a copy of the License at
//
// http://www.apache.org/licenses/LICENSE-2.0
//
// Unless required by applicable law or agreed to in writing, software
// distributed under the License is distributed on an "AS IS" BASIS,
// WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
// See the License for the specific language governing permissions and
// limitations under the License.
package tcp_test
import (
"bytes"
"fmt"
"math"
"testing"
"time"
"gvisor.googlesource.com/gvisor/pkg/tcpip"
"gvisor.googlesource.com/gvisor/pkg/tcpip/buffer"
"gvisor.googlesource.com/gvisor/pkg/tcpip/checker"
"gvisor.googlesource.com/gvisor/pkg/tcpip/header"
"gvisor.googlesource.com/gvisor/pkg/tcpip/link/loopback"
"gvisor.googlesource.com/gvisor/pkg/tcpip/link/sniffer"
"gvisor.googlesource.com/gvisor/pkg/tcpip/network/ipv4"
"gvisor.googlesource.com/gvisor/pkg/tcpip/network/ipv6"
"gvisor.googlesource.com/gvisor/pkg/tcpip/ports"
"gvisor.googlesource.com/gvisor/pkg/tcpip/seqnum"
"gvisor.googlesource.com/gvisor/pkg/tcpip/stack"
"gvisor.googlesource.com/gvisor/pkg/tcpip/transport/tcp"
"gvisor.googlesource.com/gvisor/pkg/tcpip/transport/tcp/testing/context"
"gvisor.googlesource.com/gvisor/pkg/waiter"
)
const (
// defaultMTU is the MTU, in bytes, used throughout the tests, except
// where another value is explicitly used. It is chosen to match the MTU
// of loopback interfaces on linux systems.
defaultMTU = 65535
// defaultIPv4MSS is the MSS sent by the network stack in SYN/SYN-ACK for an
// IPv4 endpoint when the MTU is set to defaultMTU in the test.
defaultIPv4MSS = defaultMTU - header.IPv4MinimumSize - header.TCPMinimumSize
)
func TestGiveUpConnect(t *testing.T) {
c := context.New(t, defaultMTU)
defer c.Cleanup()
var wq waiter.Queue
ep, err := c.Stack().NewEndpoint(tcp.ProtocolNumber, ipv4.ProtocolNumber, &wq)
if err != nil {
t.Fatalf("NewEndpoint failed: %v", err)
}
// Register for notification, then start connection attempt.
waitEntry, notifyCh := waiter.NewChannelEntry(nil)
wq.EventRegister(&waitEntry, waiter.EventOut)
defer wq.EventUnregister(&waitEntry)
if err := ep.Connect(tcpip.FullAddress{Addr: context.TestAddr, Port: context.TestPort}); err != tcpip.ErrConnectStarted {
t.Fatalf("got ep.Connect(...) = %v, want = %v", err, tcpip.ErrConnectStarted)
}
// Close the connection, wait for completion.
ep.Close()
// Wait for ep to become writable.
<-notifyCh
if err := ep.GetSockOpt(tcpip.ErrorOption{}); err != tcpip.ErrAborted {
t.Fatalf("got ep.GetSockOpt(tcpip.ErrorOption{}) = %v, want = %v", err, tcpip.ErrAborted)
}
}
func TestConnectIncrementActiveConnection(t *testing.T) {
c := context.New(t, defaultMTU)
defer c.Cleanup()
stats := c.Stack().Stats()
want := stats.TCP.ActiveConnectionOpenings.Value() + 1
c.CreateConnected(789, 30000, nil)
if got := stats.TCP.ActiveConnectionOpenings.Value(); got != want {
t.Errorf("got stats.TCP.ActtiveConnectionOpenings.Value() = %v, want = %v", got, want)
}
}
func TestConnectDoesNotIncrementFailedConnectionAttempts(t *testing.T) {
c := context.New(t, defaultMTU)
defer c.Cleanup()
stats := c.Stack().Stats()
want := stats.TCP.FailedConnectionAttempts.Value()
c.CreateConnected(789, 30000, nil)
if got := stats.TCP.FailedConnectionAttempts.Value(); got != want {
t.Errorf("got stats.TCP.FailedConnectionOpenings.Value() = %v, want = %v", got, want)
}
}
func TestActiveFailedConnectionAttemptIncrement(t *testing.T) {
c := context.New(t, defaultMTU)
defer c.Cleanup()
stats := c.Stack().Stats()
ep, err := c.Stack().NewEndpoint(tcp.ProtocolNumber, ipv4.ProtocolNumber, &c.WQ)
if err != nil {
t.Fatalf("NewEndpoint failed: %v", err)
}
c.EP = ep
want := stats.TCP.FailedConnectionAttempts.Value() + 1
if err := c.EP.Connect(tcpip.FullAddress{NIC: 2, Addr: context.TestAddr, Port: context.TestPort}); err != tcpip.ErrNoRoute {
t.Errorf("got c.EP.Connect(...) = %v, want = %v", err, tcpip.ErrNoRoute)
}
if got := stats.TCP.FailedConnectionAttempts.Value(); got != want {
t.Errorf("got stats.TCP.FailedConnectionAttempts.Value() = %v, want = %v", got, want)
}
}
func TestPassiveConnectionAttemptIncrement(t *testing.T) {
c := context.New(t, defaultMTU)
defer c.Cleanup()
stats := c.Stack().Stats()
want := stats.TCP.PassiveConnectionOpenings.Value() + 1
ep, err := c.Stack().NewEndpoint(tcp.ProtocolNumber, ipv4.ProtocolNumber, &c.WQ)
if err != nil {
t.Fatalf("NewEndpoint failed: %v", err)
}
if err := ep.Bind(tcpip.FullAddress{Addr: context.StackAddr, Port: context.StackPort}, nil); err != nil {
t.Fatalf("Bind failed: %v", err)
}
if err := ep.Listen(1); err != nil {
t.Fatalf("Listen failed: %v", err)
}
if got := stats.TCP.PassiveConnectionOpenings.Value(); got != want {
t.Errorf("got stats.TCP.PassiveConnectionOpenings.Value() = %v, want = %v", got, want)
}
}
func TestPassiveFailedConnectionAttemptIncrement(t *testing.T) {
c := context.New(t, defaultMTU)
defer c.Cleanup()
stats := c.Stack().Stats()
ep, err := c.Stack().NewEndpoint(tcp.ProtocolNumber, ipv4.ProtocolNumber, &c.WQ)
if err != nil {
t.Fatalf("NewEndpoint failed: %v", err)
}
c.EP = ep
want := stats.TCP.FailedConnectionAttempts.Value() + 1
if err := ep.Listen(1); err != tcpip.ErrInvalidEndpointState {
t.Errorf("got ep.Listen(1) = %v, want = %v", err, tcpip.ErrInvalidEndpointState)
}
if got := stats.TCP.FailedConnectionAttempts.Value(); got != want {
t.Errorf("got stats.TCP.FailedConnectionAttempts.Value() = %v, want = %v", got, want)
}
}
func TestTCPSegmentsSentIncrement(t *testing.T) {
c := context.New(t, defaultMTU)
defer c.Cleanup()
stats := c.Stack().Stats()
// SYN and ACK
want := stats.TCP.SegmentsSent.Value() + 2
c.CreateConnected(789, 30000, nil)
if got := stats.TCP.SegmentsSent.Value(); got != want {
t.Errorf("got stats.TCP.SegmentsSent.Value() = %v, want = %v", got, want)
}
}
func TestTCPResetsSentIncrement(t *testing.T) {
c := context.New(t, defaultMTU)
defer c.Cleanup()
stats := c.Stack().Stats()
wq := &waiter.Queue{}
ep, err := c.Stack().NewEndpoint(tcp.ProtocolNumber, ipv4.ProtocolNumber, wq)
if err != nil {
t.Fatalf("NewEndpoint failed: %v", err)
}
want := stats.TCP.SegmentsSent.Value() + 1
if err := ep.Bind(tcpip.FullAddress{Port: context.StackPort}, nil); err != nil {
t.Fatalf("Bind failed: %v", err)
}
if err := ep.Listen(10); err != nil {
t.Fatalf("Listen failed: %v", err)
}
// Send a SYN request.
iss := seqnum.Value(789)
c.SendPacket(nil, &context.Headers{
SrcPort: context.TestPort,
DstPort: context.StackPort,
Flags: header.TCPFlagSyn,
SeqNum: iss,
})
// Receive the SYN-ACK reply.
b := c.GetPacket()
tcp := header.TCP(header.IPv4(b).Payload())
c.IRS = seqnum.Value(tcp.SequenceNumber())
ackHeaders := &context.Headers{
SrcPort: context.TestPort,
DstPort: context.StackPort,
Flags: header.TCPFlagAck,
SeqNum: iss + 1,
// If the AckNum is not the increment of the last sequence number, a RST
// segment is sent back in response.
AckNum: c.IRS + 2,
}
// Send ACK.
c.SendPacket(nil, ackHeaders)
c.GetPacket()
if got := stats.TCP.ResetsSent.Value(); got != want {
t.Errorf("got stats.TCP.ResetsSent.Value() = %v, want = %v", got, want)
}
}
func TestTCPResetsReceivedIncrement(t *testing.T) {
c := context.New(t, defaultMTU)
defer c.Cleanup()
stats := c.Stack().Stats()
want := stats.TCP.ResetsReceived.Value() + 1
ackNum := seqnum.Value(789)
rcvWnd := seqnum.Size(30000)
c.CreateConnected(ackNum, rcvWnd, nil)
c.SendPacket(nil, &context.Headers{
SrcPort: context.TestPort,
DstPort: c.Port,
SeqNum: c.IRS.Add(2),
AckNum: ackNum.Add(2),
RcvWnd: rcvWnd,
Flags: header.TCPFlagRst,
})
if got := stats.TCP.ResetsReceived.Value(); got != want {
t.Errorf("got stats.TCP.ResetsReceived.Value() = %v, want = %v", got, want)
}
}
func TestActiveHandshake(t *testing.T) {
c := context.New(t, defaultMTU)
defer c.Cleanup()
c.CreateConnected(789, 30000, nil)
}
func TestNonBlockingClose(t *testing.T) {
c := context.New(t, defaultMTU)
defer c.Cleanup()
c.CreateConnected(789, 30000, nil)
ep := c.EP
c.EP = nil
// Close the endpoint and measure how long it takes.
t0 := time.Now()
ep.Close()
if diff := time.Now().Sub(t0); diff > 3*time.Second {
t.Fatalf("Took too long to close: %v", diff)
}
}
func TestConnectResetAfterClose(t *testing.T) {
c := context.New(t, defaultMTU)
defer c.Cleanup()
c.CreateConnected(789, 30000, nil)
ep := c.EP
c.EP = nil
// Close the endpoint, make sure we get a FIN segment, then acknowledge
// to complete closure of sender, but don't send our own FIN.
ep.Close()
checker.IPv4(t, c.GetPacket(),
checker.TCP(
checker.DstPort(context.TestPort),
checker.SeqNum(uint32(c.IRS)+1),
checker.AckNum(790),
checker.TCPFlags(header.TCPFlagAck|header.TCPFlagFin),
),
)
c.SendPacket(nil, &context.Headers{
SrcPort: context.TestPort,
DstPort: c.Port,
Flags: header.TCPFlagAck,
SeqNum: 790,
AckNum: c.IRS.Add(1),
RcvWnd: 30000,
})
// Wait for the ep to give up waiting for a FIN, and send a RST.
time.Sleep(3 * time.Second)
for {
b := c.GetPacket()
tcp := header.TCP(header.IPv4(b).Payload())
if tcp.Flags() == header.TCPFlagAck|header.TCPFlagFin {
// This is a retransmit of the FIN, ignore it.
continue
}
checker.IPv4(t, b,
checker.TCP(
checker.DstPort(context.TestPort),
checker.SeqNum(uint32(c.IRS)+1),
checker.AckNum(790),
checker.TCPFlags(header.TCPFlagAck|header.TCPFlagRst),
),
)
break
}
}
func TestSimpleReceive(t *testing.T) {
c := context.New(t, defaultMTU)
defer c.Cleanup()
c.CreateConnected(789, 30000, nil)
we, ch := waiter.NewChannelEntry(nil)
c.WQ.EventRegister(&we, waiter.EventIn)
defer c.WQ.EventUnregister(&we)
if _, _, err := c.EP.Read(nil); err != tcpip.ErrWouldBlock {
t.Fatalf("got c.EP.Read(nil) = %v, want = %v", err, tcpip.ErrWouldBlock)
}
data := []byte{1, 2, 3}
c.SendPacket(data, &context.Headers{
SrcPort: context.TestPort,
DstPort: c.Port,
Flags: header.TCPFlagAck,
SeqNum: 790,
AckNum: c.IRS.Add(1),
RcvWnd: 30000,
})
// Wait for receive to be notified.
select {
case <-ch:
case <-time.After(1 * time.Second):
t.Fatalf("Timed out waiting for data to arrive")
}
// Receive data.
v, _, err := c.EP.Read(nil)
if err != nil {
t.Fatalf("Read failed: %v", err)
}
if !bytes.Equal(data, v) {
t.Fatalf("got data = %v, want = %v", v, data)
}
// Check that ACK is received.
checker.IPv4(t, c.GetPacket(),
checker.TCP(
checker.DstPort(context.TestPort),
checker.SeqNum(uint32(c.IRS)+1),
checker.AckNum(uint32(790+len(data))),
checker.TCPFlags(header.TCPFlagAck),
),
)
}
func TestOutOfOrderReceive(t *testing.T) {
c := context.New(t, defaultMTU)
defer c.Cleanup()
c.CreateConnected(789, 30000, nil)
we, ch := waiter.NewChannelEntry(nil)
c.WQ.EventRegister(&we, waiter.EventIn)
defer c.WQ.EventUnregister(&we)
if _, _, err := c.EP.Read(nil); err != tcpip.ErrWouldBlock {
t.Fatalf("got c.EP.Read(nil) = %v, want = %v", err, tcpip.ErrWouldBlock)
}
// Send second half of data first, with seqnum 3 ahead of expected.
data := []byte{1, 2, 3, 4, 5, 6}
c.SendPacket(data[3:], &context.Headers{
SrcPort: context.TestPort,
DstPort: c.Port,
Flags: header.TCPFlagAck,
SeqNum: 793,
AckNum: c.IRS.Add(1),
RcvWnd: 30000,
})
// Check that we get an ACK specifying which seqnum is expected.
checker.IPv4(t, c.GetPacket(),
checker.TCP(
checker.DstPort(context.TestPort),
checker.SeqNum(uint32(c.IRS)+1),
checker.AckNum(790),
checker.TCPFlags(header.TCPFlagAck),
),
)
// Wait 200ms and check that no data has been received.
time.Sleep(200 * time.Millisecond)
if _, _, err := c.EP.Read(nil); err != tcpip.ErrWouldBlock {
t.Fatalf("got c.EP.Read(nil) = %v, want = %v", err, tcpip.ErrWouldBlock)
}
// Send the first 3 bytes now.
c.SendPacket(data[:3], &context.Headers{
SrcPort: context.TestPort,
DstPort: c.Port,
Flags: header.TCPFlagAck,
SeqNum: 790,
AckNum: c.IRS.Add(1),
RcvWnd: 30000,
})
// Receive data.
read := make([]byte, 0, 6)
for len(read) < len(data) {
v, _, err := c.EP.Read(nil)
if err != nil {
if err == tcpip.ErrWouldBlock {
// Wait for receive to be notified.
select {
case <-ch:
case <-time.After(5 * time.Second):
t.Fatalf("Timed out waiting for data to arrive")
}
continue
}
t.Fatalf("Read failed: %v", err)
}
read = append(read, v...)
}
// Check that we received the data in proper order.
if !bytes.Equal(data, read) {
t.Fatalf("got data = %v, want = %v", read, data)
}
// Check that the whole data is acknowledged.
checker.IPv4(t, c.GetPacket(),
checker.TCP(
checker.DstPort(context.TestPort),
checker.SeqNum(uint32(c.IRS)+1),
checker.AckNum(uint32(790+len(data))),
checker.TCPFlags(header.TCPFlagAck),
),
)
}
func TestOutOfOrderFlood(t *testing.T) {
c := context.New(t, defaultMTU)
defer c.Cleanup()
// Create a new connection with initial window size of 10.
opt := tcpip.ReceiveBufferSizeOption(10)
c.CreateConnected(789, 30000, &opt)
if _, _, err := c.EP.Read(nil); err != tcpip.ErrWouldBlock {
t.Fatalf("got c.EP.Read(nil) = %v, want = %v", err, tcpip.ErrWouldBlock)
}
// Send 100 packets before the actual one that is expected.
data := []byte{1, 2, 3, 4, 5, 6}
for i := 0; i < 100; i++ {
c.SendPacket(data[3:], &context.Headers{
SrcPort: context.TestPort,
DstPort: c.Port,
Flags: header.TCPFlagAck,
SeqNum: 796,
AckNum: c.IRS.Add(1),
RcvWnd: 30000,
})
checker.IPv4(t, c.GetPacket(),
checker.TCP(
checker.DstPort(context.TestPort),
checker.SeqNum(uint32(c.IRS)+1),
checker.AckNum(790),
checker.TCPFlags(header.TCPFlagAck),
),
)
}
// Send packet with seqnum 793. It must be discarded because the
// out-of-order buffer was filled by the previous packets.
c.SendPacket(data[3:], &context.Headers{
SrcPort: context.TestPort,
DstPort: c.Port,
Flags: header.TCPFlagAck,
SeqNum: 793,
AckNum: c.IRS.Add(1),
RcvWnd: 30000,
})
checker.IPv4(t, c.GetPacket(),
checker.TCP(
checker.DstPort(context.TestPort),
checker.SeqNum(uint32(c.IRS)+1),
checker.AckNum(790),
checker.TCPFlags(header.TCPFlagAck),
),
)
// Now send the expected packet, seqnum 790.
c.SendPacket(data[:3], &context.Headers{
SrcPort: context.TestPort,
DstPort: c.Port,
Flags: header.TCPFlagAck,
SeqNum: 790,
AckNum: c.IRS.Add(1),
RcvWnd: 30000,
})
// Check that only packet 790 is acknowledged.
checker.IPv4(t, c.GetPacket(),
checker.TCP(
checker.DstPort(context.TestPort),
checker.SeqNum(uint32(c.IRS)+1),
checker.AckNum(793),
checker.TCPFlags(header.TCPFlagAck),
),
)
}
func TestRstOnCloseWithUnreadData(t *testing.T) {
c := context.New(t, defaultMTU)
defer c.Cleanup()
c.CreateConnected(789, 30000, nil)
we, ch := waiter.NewChannelEntry(nil)
c.WQ.EventRegister(&we, waiter.EventIn)
defer c.WQ.EventUnregister(&we)
if _, _, err := c.EP.Read(nil); err != tcpip.ErrWouldBlock {
t.Fatalf("got c.EP.Read(nil) = %v, want = %v", err, tcpip.ErrWouldBlock)
}
data := []byte{1, 2, 3}
c.SendPacket(data, &context.Headers{
SrcPort: context.TestPort,
DstPort: c.Port,
Flags: header.TCPFlagAck,
SeqNum: 790,
AckNum: c.IRS.Add(1),
RcvWnd: 30000,
})
// Wait for receive to be notified.
select {
case <-ch:
case <-time.After(3 * time.Second):
t.Fatalf("Timed out waiting for data to arrive")
}
// Check that ACK is received, this happens regardless of the read.
checker.IPv4(t, c.GetPacket(),
checker.TCP(
checker.DstPort(context.TestPort),
checker.SeqNum(uint32(c.IRS)+1),
checker.AckNum(uint32(790+len(data))),
checker.TCPFlags(header.TCPFlagAck),
),
)
// Now that we know we have unread data, let's just close the connection
// and verify that netstack sends an RST rather than a FIN.
c.EP.Close()
checker.IPv4(t, c.GetPacket(),
checker.TCP(
checker.DstPort(context.TestPort),
checker.TCPFlags(header.TCPFlagAck|header.TCPFlagRst),
// We shouldn't consume a sequence number on RST.
checker.SeqNum(uint32(c.IRS)+1),
))
// This final should be ignored because an ACK on a reset doesn't
// mean anything.
c.SendPacket(nil, &context.Headers{
SrcPort: context.TestPort,
DstPort: c.Port,
Flags: header.TCPFlagAck,
SeqNum: seqnum.Value(790 + len(data)),
AckNum: c.IRS.Add(seqnum.Size(2)),
RcvWnd: 30000,
})
}
func TestRstOnCloseWithUnreadDataFinConvertRst(t *testing.T) {
c := context.New(t, defaultMTU)
defer c.Cleanup()
c.CreateConnected(789, 30000, nil)
we, ch := waiter.NewChannelEntry(nil)
c.WQ.EventRegister(&we, waiter.EventIn)
defer c.WQ.EventUnregister(&we)
if _, _, err := c.EP.Read(nil); err != tcpip.ErrWouldBlock {
t.Fatalf("got c.EP.Read(nil) = %v, want = %v", err, tcpip.ErrWouldBlock)
}
data := []byte{1, 2, 3}
c.SendPacket(data, &context.Headers{
SrcPort: context.TestPort,
DstPort: c.Port,
Flags: header.TCPFlagAck,
SeqNum: 790,
AckNum: c.IRS.Add(1),
RcvWnd: 30000,
})
// Wait for receive to be notified.
select {
case <-ch:
case <-time.After(3 * time.Second):
t.Fatalf("Timed out waiting for data to arrive")
}
// Check that ACK is received, this happens regardless of the read.
checker.IPv4(t, c.GetPacket(),
checker.TCP(
checker.DstPort(context.TestPort),
checker.SeqNum(uint32(c.IRS)+1),
checker.AckNum(uint32(790+len(data))),
checker.TCPFlags(header.TCPFlagAck),
),
)
// Cause a FIN to be generated.
c.EP.Shutdown(tcpip.ShutdownWrite)
// Make sure we get the FIN but DON't ACK IT.
checker.IPv4(t, c.GetPacket(),
checker.TCP(
checker.DstPort(context.TestPort),
checker.TCPFlags(header.TCPFlagAck|header.TCPFlagFin),
checker.SeqNum(uint32(c.IRS)+1),
))
// Cause a RST to be generated by closing the read end now since we have
// unread data.
c.EP.Shutdown(tcpip.ShutdownRead)
// Make sure we get the RST
checker.IPv4(t, c.GetPacket(),
checker.TCP(
checker.DstPort(context.TestPort),
checker.TCPFlags(header.TCPFlagAck|header.TCPFlagRst),
// We shouldn't consume a sequence number on RST.
checker.SeqNum(uint32(c.IRS)+1),
))
// The ACK to the FIN should now be rejected since the connection has been
// closed by a RST.
c.SendPacket(nil, &context.Headers{
SrcPort: context.TestPort,
DstPort: c.Port,
Flags: header.TCPFlagAck,
SeqNum: seqnum.Value(790 + len(data)),
AckNum: c.IRS.Add(seqnum.Size(2)),
RcvWnd: 30000,
})
}
func TestFullWindowReceive(t *testing.T) {
c := context.New(t, defaultMTU)
defer c.Cleanup()
opt := tcpip.ReceiveBufferSizeOption(10)
c.CreateConnected(789, 30000, &opt)
we, ch := waiter.NewChannelEntry(nil)
c.WQ.EventRegister(&we, waiter.EventIn)
defer c.WQ.EventUnregister(&we)
_, _, err := c.EP.Read(nil)
if err != tcpip.ErrWouldBlock {
t.Fatalf("Read failed: %v", err)
}
// Fill up the window.
data := []byte{1, 2, 3, 4, 5, 6, 7, 8, 9, 10}
c.SendPacket(data, &context.Headers{
SrcPort: context.TestPort,
DstPort: c.Port,
Flags: header.TCPFlagAck,
SeqNum: 790,
AckNum: c.IRS.Add(1),
RcvWnd: 30000,
})
// Wait for receive to be notified.
select {
case <-ch:
case <-time.After(5 * time.Second):
t.Fatalf("Timed out waiting for data to arrive")
}
// Check that data is acknowledged, and window goes to zero.
checker.IPv4(t, c.GetPacket(),
checker.TCP(
checker.DstPort(context.TestPort),
checker.SeqNum(uint32(c.IRS)+1),
checker.AckNum(uint32(790+len(data))),
checker.TCPFlags(header.TCPFlagAck),
checker.Window(0),
),
)
// Receive data and check it.
v, _, err := c.EP.Read(nil)
if err != nil {
t.Fatalf("Read failed: %v", err)
}
if !bytes.Equal(data, v) {
t.Fatalf("got data = %v, want = %v", v, data)
}
// Check that we get an ACK for the newly non-zero window.
checker.IPv4(t, c.GetPacket(),
checker.TCP(
checker.DstPort(context.TestPort),
checker.SeqNum(uint32(c.IRS)+1),
checker.AckNum(uint32(790+len(data))),
checker.TCPFlags(header.TCPFlagAck),
checker.Window(10),
),
)
}
func TestNoWindowShrinking(t *testing.T) {
c := context.New(t, defaultMTU)
defer c.Cleanup()
// Start off with a window size of 10, then shrink it to 5.
opt := tcpip.ReceiveBufferSizeOption(10)
c.CreateConnected(789, 30000, &opt)
opt = 5
if err := c.EP.SetSockOpt(opt); err != nil {
t.Fatalf("SetSockOpt failed: %v", err)
}
we, ch := waiter.NewChannelEntry(nil)
c.WQ.EventRegister(&we, waiter.EventIn)
defer c.WQ.EventUnregister(&we)
if _, _, err := c.EP.Read(nil); err != tcpip.ErrWouldBlock {
t.Fatalf("got c.EP.Read(nil) = %v, want = %v", err, tcpip.ErrWouldBlock)
}
// Send 3 bytes, check that the peer acknowledges them.
data := []byte{1, 2, 3, 4, 5, 6, 7, 8, 9, 10}
c.SendPacket(data[:3], &context.Headers{
SrcPort: context.TestPort,
DstPort: c.Port,
Flags: header.TCPFlagAck,
SeqNum: 790,
AckNum: c.IRS.Add(1),
RcvWnd: 30000,
})
// Wait for receive to be notified.
select {
case <-ch:
case <-time.After(5 * time.Second):
t.Fatalf("Timed out waiting for data to arrive")
}
// Check that data is acknowledged, and that window doesn't go to zero
// just yet because it was previously set to 10. It must go to 7 now.
checker.IPv4(t, c.GetPacket(),
checker.TCP(
checker.DstPort(context.TestPort),
checker.SeqNum(uint32(c.IRS)+1),
checker.AckNum(793),
checker.TCPFlags(header.TCPFlagAck),
checker.Window(7),
),
)
// Send 7 more bytes, check that the window fills up.
c.SendPacket(data[3:], &context.Headers{
SrcPort: context.TestPort,
DstPort: c.Port,
Flags: header.TCPFlagAck,
SeqNum: 793,
AckNum: c.IRS.Add(1),
RcvWnd: 30000,
})
select {
case <-ch:
case <-time.After(5 * time.Second):
t.Fatalf("Timed out waiting for data to arrive")
}
checker.IPv4(t, c.GetPacket(),
checker.TCP(
checker.DstPort(context.TestPort),
checker.SeqNum(uint32(c.IRS)+1),
checker.AckNum(uint32(790+len(data))),
checker.TCPFlags(header.TCPFlagAck),
checker.Window(0),
),
)
// Receive data and check it.
read := make([]byte, 0, 10)
for len(read) < len(data) {
v, _, err := c.EP.Read(nil)
if err != nil {
t.Fatalf("Read failed: %v", err)
}
read = append(read, v...)
}
if !bytes.Equal(data, read) {
t.Fatalf("got data = %v, want = %v", read, data)
}
// Check that we get an ACK for the newly non-zero window, which is the
// new size.
checker.IPv4(t, c.GetPacket(),
checker.TCP(
checker.DstPort(context.TestPort),
checker.SeqNum(uint32(c.IRS)+1),
checker.AckNum(uint32(790+len(data))),
checker.TCPFlags(header.TCPFlagAck),
checker.Window(5),
),
)
}
func TestSimpleSend(t *testing.T) {
c := context.New(t, defaultMTU)
defer c.Cleanup()
c.CreateConnected(789, 30000, nil)
data := []byte{1, 2, 3}
view := buffer.NewView(len(data))
copy(view, data)
if _, _, err := c.EP.Write(tcpip.SlicePayload(view), tcpip.WriteOptions{}); err != nil {
t.Fatalf("Write failed: %v", err)
}
// Check that data is received.
b := c.GetPacket()
checker.IPv4(t, b,
checker.PayloadLen(len(data)+header.TCPMinimumSize),
checker.TCP(
checker.DstPort(context.TestPort),
checker.SeqNum(uint32(c.IRS)+1),
checker.AckNum(790),
checker.TCPFlagsMatch(header.TCPFlagAck, ^uint8(header.TCPFlagPsh)),
),
)
if p := b[header.IPv4MinimumSize+header.TCPMinimumSize:]; !bytes.Equal(data, p) {
t.Fatalf("got data = %v, want = %v", p, data)
}
// Acknowledge the data.
c.SendPacket(nil, &context.Headers{
SrcPort: context.TestPort,
DstPort: c.Port,
Flags: header.TCPFlagAck,
SeqNum: 790,
AckNum: c.IRS.Add(1 + seqnum.Size(len(data))),
RcvWnd: 30000,
})
}
func TestZeroWindowSend(t *testing.T) {
c := context.New(t, defaultMTU)
defer c.Cleanup()
c.CreateConnected(789, 0, nil)
data := []byte{1, 2, 3}
view := buffer.NewView(len(data))
copy(view, data)
_, _, err := c.EP.Write(tcpip.SlicePayload(view), tcpip.WriteOptions{})
if err != nil {
t.Fatalf("Write failed: %v", err)
}
// Since the window is currently zero, check that no packet is received.
c.CheckNoPacket("Packet received when window is zero")
// Open up the window. Data should be received now.
c.SendPacket(nil, &context.Headers{
SrcPort: context.TestPort,
DstPort: c.Port,
Flags: header.TCPFlagAck,
SeqNum: 790,
AckNum: c.IRS.Add(1),
RcvWnd: 30000,
})
// Check that data is received.
b := c.GetPacket()
checker.IPv4(t, b,
checker.PayloadLen(len(data)+header.TCPMinimumSize),
checker.TCP(
checker.DstPort(context.TestPort),
checker.SeqNum(uint32(c.IRS)+1),
checker.AckNum(790),
checker.TCPFlagsMatch(header.TCPFlagAck, ^uint8(header.TCPFlagPsh)),
),
)
if p := b[header.IPv4MinimumSize+header.TCPMinimumSize:]; !bytes.Equal(data, p) {
t.Fatalf("got data = %v, want = %v", p, data)
}
// Acknowledge the data.
c.SendPacket(nil, &context.Headers{
SrcPort: context.TestPort,
DstPort: c.Port,
Flags: header.TCPFlagAck,
SeqNum: 790,
AckNum: c.IRS.Add(1 + seqnum.Size(len(data))),
RcvWnd: 30000,
})
}
func TestScaledWindowConnect(t *testing.T) {
// This test ensures that window scaling is used when the peer
// does advertise it and connection is established with Connect().
c := context.New(t, defaultMTU)
defer c.Cleanup()
// Set the window size greater than the maximum non-scaled window.
opt := tcpip.ReceiveBufferSizeOption(65535 * 3)
c.CreateConnectedWithRawOptions(789, 30000, &opt, []byte{
header.TCPOptionWS, 3, 0, header.TCPOptionNOP,
})
data := []byte{1, 2, 3}
view := buffer.NewView(len(data))
copy(view, data)
if _, _, err := c.EP.Write(tcpip.SlicePayload(view), tcpip.WriteOptions{}); err != nil {
t.Fatalf("Write failed: %v", err)
}
// Check that data is received, and that advertised window is 0xbfff,
// that is, that it is scaled.
b := c.GetPacket()
checker.IPv4(t, b,
checker.PayloadLen(len(data)+header.TCPMinimumSize),
checker.TCP(
checker.DstPort(context.TestPort),
checker.SeqNum(uint32(c.IRS)+1),
checker.AckNum(790),
checker.Window(0xbfff),
checker.TCPFlagsMatch(header.TCPFlagAck, ^uint8(header.TCPFlagPsh)),
),
)
}
func TestNonScaledWindowConnect(t *testing.T) {
// This test ensures that window scaling is not used when the peer
// doesn't advertise it and connection is established with Connect().
c := context.New(t, defaultMTU)
defer c.Cleanup()
// Set the window size greater than the maximum non-scaled window.
opt := tcpip.ReceiveBufferSizeOption(65535 * 3)
c.CreateConnected(789, 30000, &opt)
data := []byte{1, 2, 3}
view := buffer.NewView(len(data))
copy(view, data)
if _, _, err := c.EP.Write(tcpip.SlicePayload(view), tcpip.WriteOptions{}); err != nil {
t.Fatalf("Write failed: %v", err)
}
// Check that data is received, and that advertised window is 0xffff,
// that is, that it's not scaled.
b := c.GetPacket()
checker.IPv4(t, b,
checker.PayloadLen(len(data)+header.TCPMinimumSize),
checker.TCP(
checker.DstPort(context.TestPort),
checker.SeqNum(uint32(c.IRS)+1),
checker.AckNum(790),
checker.Window(0xffff),
checker.TCPFlagsMatch(header.TCPFlagAck, ^uint8(header.TCPFlagPsh)),
),
)
}
func TestScaledWindowAccept(t *testing.T) {
// This test ensures that window scaling is used when the peer
// does advertise it and connection is established with Accept().
c := context.New(t, defaultMTU)
defer c.Cleanup()
// Create EP and start listening.
wq := &waiter.Queue{}
ep, err := c.Stack().NewEndpoint(tcp.ProtocolNumber, ipv4.ProtocolNumber, wq)
if err != nil {
t.Fatalf("NewEndpoint failed: %v", err)
}
defer ep.Close()
// Set the window size greater than the maximum non-scaled window.
if err := ep.SetSockOpt(tcpip.ReceiveBufferSizeOption(65535 * 3)); err != nil {
t.Fatalf("SetSockOpt failed failed: %v", err)
}
if err := ep.Bind(tcpip.FullAddress{Port: context.StackPort}, nil); err != nil {
t.Fatalf("Bind failed: %v", err)
}
if err := ep.Listen(10); err != nil {
t.Fatalf("Listen failed: %v", err)
}
// Do 3-way handshake.
c.PassiveConnectWithOptions(100, 2, header.TCPSynOptions{MSS: defaultIPv4MSS})
// Try to accept the connection.
we, ch := waiter.NewChannelEntry(nil)
wq.EventRegister(&we, waiter.EventIn)
defer wq.EventUnregister(&we)
c.EP, _, err = ep.Accept()
if err == tcpip.ErrWouldBlock {
// Wait for connection to be established.
select {
case <-ch:
c.EP, _, err = ep.Accept()
if err != nil {
t.Fatalf("Accept failed: %v", err)
}
case <-time.After(1 * time.Second):
t.Fatalf("Timed out waiting for accept")
}
}
data := []byte{1, 2, 3}
view := buffer.NewView(len(data))
copy(view, data)
if _, _, err := c.EP.Write(tcpip.SlicePayload(view), tcpip.WriteOptions{}); err != nil {
t.Fatalf("Write failed: %v", err)
}
// Check that data is received, and that advertised window is 0xbfff,
// that is, that it is scaled.
b := c.GetPacket()
checker.IPv4(t, b,
checker.PayloadLen(len(data)+header.TCPMinimumSize),
checker.TCP(
checker.DstPort(context.TestPort),
checker.SeqNum(uint32(c.IRS)+1),
checker.AckNum(790),
checker.Window(0xbfff),
checker.TCPFlagsMatch(header.TCPFlagAck, ^uint8(header.TCPFlagPsh)),
),
)
}
func TestNonScaledWindowAccept(t *testing.T) {
// This test ensures that window scaling is not used when the peer
// doesn't advertise it and connection is established with Accept().
c := context.New(t, defaultMTU)
defer c.Cleanup()
// Create EP and start listening.
wq := &waiter.Queue{}
ep, err := c.Stack().NewEndpoint(tcp.ProtocolNumber, ipv4.ProtocolNumber, wq)
if err != nil {
t.Fatalf("NewEndpoint failed: %v", err)
}
defer ep.Close()
// Set the window size greater than the maximum non-scaled window.
if err := ep.SetSockOpt(tcpip.ReceiveBufferSizeOption(65535 * 3)); err != nil {
t.Fatalf("SetSockOpt failed failed: %v", err)
}
if err := ep.Bind(tcpip.FullAddress{Port: context.StackPort}, nil); err != nil {
t.Fatalf("Bind failed: %v", err)
}
if err := ep.Listen(10); err != nil {
t.Fatalf("Listen failed: %v", err)
}
// Do 3-way handshake.
c.PassiveConnect(100, 2, header.TCPSynOptions{MSS: defaultIPv4MSS})
// Try to accept the connection.
we, ch := waiter.NewChannelEntry(nil)
wq.EventRegister(&we, waiter.EventIn)
defer wq.EventUnregister(&we)
c.EP, _, err = ep.Accept()
if err == tcpip.ErrWouldBlock {
// Wait for connection to be established.
select {
case <-ch:
c.EP, _, err = ep.Accept()
if err != nil {
t.Fatalf("Accept failed: %v", err)
}
case <-time.After(1 * time.Second):
t.Fatalf("Timed out waiting for accept")
}
}
data := []byte{1, 2, 3}
view := buffer.NewView(len(data))
copy(view, data)
if _, _, err := c.EP.Write(tcpip.SlicePayload(view), tcpip.WriteOptions{}); err != nil {
t.Fatalf("Write failed: %v", err)
}
// Check that data is received, and that advertised window is 0xffff,
// that is, that it's not scaled.
b := c.GetPacket()
checker.IPv4(t, b,
checker.PayloadLen(len(data)+header.TCPMinimumSize),
checker.TCP(
checker.DstPort(context.TestPort),
checker.SeqNum(uint32(c.IRS)+1),
checker.AckNum(790),
checker.Window(0xffff),
checker.TCPFlagsMatch(header.TCPFlagAck, ^uint8(header.TCPFlagPsh)),
),
)
}
func TestZeroScaledWindowReceive(t *testing.T) {
// This test ensures that the endpoint sends a non-zero window size
// advertisement when the scaled window transitions from 0 to non-zero,
// but the actual window (not scaled) hasn't gotten to zero.
c := context.New(t, defaultMTU)
defer c.Cleanup()
// Set the window size such that a window scale of 4 will be used.
const wnd = 65535 * 10
const ws = uint32(4)
opt := tcpip.ReceiveBufferSizeOption(wnd)
c.CreateConnectedWithRawOptions(789, 30000, &opt, []byte{
header.TCPOptionWS, 3, 0, header.TCPOptionNOP,
})
// Write chunks of 50000 bytes.
remain := wnd
sent := 0
data := make([]byte, 50000)
for remain > len(data) {
c.SendPacket(data, &context.Headers{
SrcPort: context.TestPort,
DstPort: c.Port,
Flags: header.TCPFlagAck,
SeqNum: seqnum.Value(790 + sent),
AckNum: c.IRS.Add(1),
RcvWnd: 30000,
})
sent += len(data)
remain -= len(data)
checker.IPv4(t, c.GetPacket(),
checker.PayloadLen(header.TCPMinimumSize),
checker.TCP(
checker.DstPort(context.TestPort),
checker.SeqNum(uint32(c.IRS)+1),
checker.AckNum(uint32(790+sent)),
checker.Window(uint16(remain>>ws)),
checker.TCPFlags(header.TCPFlagAck),
),
)
}
// Make the window non-zero, but the scaled window zero.
if remain >= 16 {
data = data[:remain-15]
c.SendPacket(data, &context.Headers{
SrcPort: context.TestPort,
DstPort: c.Port,
Flags: header.TCPFlagAck,
SeqNum: seqnum.Value(790 + sent),
AckNum: c.IRS.Add(1),
RcvWnd: 30000,
})
sent += len(data)
remain -= len(data)
checker.IPv4(t, c.GetPacket(),
checker.PayloadLen(header.TCPMinimumSize),
checker.TCP(
checker.DstPort(context.TestPort),
checker.SeqNum(uint32(c.IRS)+1),
checker.AckNum(uint32(790+sent)),
checker.Window(0),
checker.TCPFlags(header.TCPFlagAck),
),
)
}
// Read some data. An ack should be sent in response to that.
v, _, err := c.EP.Read(nil)
if err != nil {
t.Fatalf("Read failed: %v", err)
}
checker.IPv4(t, c.GetPacket(),
checker.PayloadLen(header.TCPMinimumSize),
checker.TCP(
checker.DstPort(context.TestPort),
checker.SeqNum(uint32(c.IRS)+1),
checker.AckNum(uint32(790+sent)),
checker.Window(uint16(len(v)>>ws)),
checker.TCPFlags(header.TCPFlagAck),
),
)
}
func TestSegmentMerging(t *testing.T) {
tests := []struct {
name string
stop func(tcpip.Endpoint)
resume func(tcpip.Endpoint)
}{
{
"stop work",
func(ep tcpip.Endpoint) {
ep.(interface{ StopWork() }).StopWork()
},
func(ep tcpip.Endpoint) {
ep.(interface{ ResumeWork() }).ResumeWork()
},
},
{
"cork",
func(ep tcpip.Endpoint) {
ep.SetSockOpt(tcpip.CorkOption(1))
},
func(ep tcpip.Endpoint) {
ep.SetSockOpt(tcpip.CorkOption(0))
},
},
}
for _, test := range tests {
t.Run(test.name, func(t *testing.T) {
c := context.New(t, defaultMTU)
defer c.Cleanup()
c.CreateConnected(789, 30000, nil)
// Prevent the endpoint from processing packets.
test.stop(c.EP)
var allData []byte
for i, data := range [][]byte{{1, 2, 3, 4}, {5, 6, 7}, {8, 9}, {10}, {11}} {
allData = append(allData, data...)
view := buffer.NewViewFromBytes(data)
if _, _, err := c.EP.Write(tcpip.SlicePayload(view), tcpip.WriteOptions{}); err != nil {
t.Fatalf("Write #%d failed: %v", i+1, err)
}
}
// Let the endpoint process the segments that we just sent.
test.resume(c.EP)
// Check that data is received.
b := c.GetPacket()
checker.IPv4(t, b,
checker.PayloadLen(len(allData)+header.TCPMinimumSize),
checker.TCP(
checker.DstPort(context.TestPort),
checker.SeqNum(uint32(c.IRS)+1),
checker.AckNum(790),
checker.TCPFlagsMatch(header.TCPFlagAck, ^uint8(header.TCPFlagPsh)),
),
)
if got := b[header.IPv4MinimumSize+header.TCPMinimumSize:]; !bytes.Equal(got, allData) {
t.Fatalf("got data = %v, want = %v", got, allData)
}
// Acknowledge the data.
c.SendPacket(nil, &context.Headers{
SrcPort: context.TestPort,
DstPort: c.Port,
Flags: header.TCPFlagAck,
SeqNum: 790,
AckNum: c.IRS.Add(1 + seqnum.Size(len(allData))),
RcvWnd: 30000,
})
})
}
}
func TestDelay(t *testing.T) {
c := context.New(t, defaultMTU)
defer c.Cleanup()
c.CreateConnected(789, 30000, nil)
c.EP.SetSockOpt(tcpip.DelayOption(1))
var allData []byte
for i, data := range [][]byte{{0}, {1, 2, 3, 4}, {5, 6, 7}, {8, 9}, {10}, {11}} {
allData = append(allData, data...)
view := buffer.NewViewFromBytes(data)
if _, _, err := c.EP.Write(tcpip.SlicePayload(view), tcpip.WriteOptions{}); err != nil {
t.Fatalf("Write #%d failed: %v", i+1, err)
}
}
seq := c.IRS.Add(1)
for _, want := range [][]byte{allData[:1], allData[1:]} {
// Check that data is received.
b := c.GetPacket()
checker.IPv4(t, b,
checker.PayloadLen(len(want)+header.TCPMinimumSize),
checker.TCP(
checker.DstPort(context.TestPort),
checker.SeqNum(uint32(seq)),
checker.AckNum(790),
checker.TCPFlagsMatch(header.TCPFlagAck, ^uint8(header.TCPFlagPsh)),
),
)
if got := b[header.IPv4MinimumSize+header.TCPMinimumSize:]; !bytes.Equal(got, want) {
t.Fatalf("got data = %v, want = %v", got, want)
}
seq = seq.Add(seqnum.Size(len(want)))
// Acknowledge the data.
c.SendPacket(nil, &context.Headers{
SrcPort: context.TestPort,
DstPort: c.Port,
Flags: header.TCPFlagAck,
SeqNum: 790,
AckNum: seq,
RcvWnd: 30000,
})
}
}
func TestUndelay(t *testing.T) {
c := context.New(t, defaultMTU)
defer c.Cleanup()
c.CreateConnected(789, 30000, nil)
c.EP.SetSockOpt(tcpip.DelayOption(1))
allData := [][]byte{{0}, {1, 2, 3}}
for i, data := range allData {
view := buffer.NewViewFromBytes(data)
if _, _, err := c.EP.Write(tcpip.SlicePayload(view), tcpip.WriteOptions{}); err != nil {
t.Fatalf("Write #%d failed: %v", i+1, err)
}
}
seq := c.IRS.Add(1)
// Check that data is received.
first := c.GetPacket()
checker.IPv4(t, first,
checker.PayloadLen(len(allData[0])+header.TCPMinimumSize),
checker.TCP(
checker.DstPort(context.TestPort),
checker.SeqNum(uint32(seq)),
checker.AckNum(790),
checker.TCPFlagsMatch(header.TCPFlagAck, ^uint8(header.TCPFlagPsh)),
),
)
if got, want := first[header.IPv4MinimumSize+header.TCPMinimumSize:], allData[0]; !bytes.Equal(got, want) {
t.Fatalf("got first packet's data = %v, want = %v", got, want)
}
seq = seq.Add(seqnum.Size(len(allData[0])))
// Check that we don't get the second packet yet.
c.CheckNoPacketTimeout("delayed second packet transmitted", 100*time.Millisecond)
c.EP.SetSockOpt(tcpip.DelayOption(0))
// Check that data is received.
second := c.GetPacket()
checker.IPv4(t, second,
checker.PayloadLen(len(allData[1])+header.TCPMinimumSize),
checker.TCP(
checker.DstPort(context.TestPort),
checker.SeqNum(uint32(seq)),
checker.AckNum(790),
checker.TCPFlagsMatch(header.TCPFlagAck, ^uint8(header.TCPFlagPsh)),
),
)
if got, want := second[header.IPv4MinimumSize+header.TCPMinimumSize:], allData[1]; !bytes.Equal(got, want) {
t.Fatalf("got second packet's data = %v, want = %v", got, want)
}
seq = seq.Add(seqnum.Size(len(allData[1])))
// Acknowledge the data.
c.SendPacket(nil, &context.Headers{
SrcPort: context.TestPort,
DstPort: c.Port,
Flags: header.TCPFlagAck,
SeqNum: 790,
AckNum: seq,
RcvWnd: 30000,
})
}
func TestMSSNotDelayed(t *testing.T) {
tests := []struct {
name string
fn func(tcpip.Endpoint)
}{
{"no-op", func(tcpip.Endpoint) {}},
{"delay", func(ep tcpip.Endpoint) { ep.SetSockOpt(tcpip.DelayOption(1)) }},
{"cork", func(ep tcpip.Endpoint) { ep.SetSockOpt(tcpip.CorkOption(1)) }},
}
for _, test := range tests {
t.Run(test.name, func(t *testing.T) {
const maxPayload = 100
c := context.New(t, defaultMTU)
defer c.Cleanup()
c.CreateConnectedWithRawOptions(789, 30000, nil, []byte{
header.TCPOptionMSS, 4, byte(maxPayload / 256), byte(maxPayload % 256),
})
test.fn(c.EP)
allData := [][]byte{{0}, make([]byte, maxPayload), make([]byte, maxPayload)}
for i, data := range allData {
view := buffer.NewViewFromBytes(data)
if _, _, err := c.EP.Write(tcpip.SlicePayload(view), tcpip.WriteOptions{}); err != nil {
t.Fatalf("Write #%d failed: %v", i+1, err)
}
}
seq := c.IRS.Add(1)
for i, data := range allData {
// Check that data is received.
packet := c.GetPacket()
checker.IPv4(t, packet,
checker.PayloadLen(len(data)+header.TCPMinimumSize),
checker.TCP(
checker.DstPort(context.TestPort),
checker.SeqNum(uint32(seq)),
checker.AckNum(790),
checker.TCPFlagsMatch(header.TCPFlagAck, ^uint8(header.TCPFlagPsh)),
),
)
if got, want := packet[header.IPv4MinimumSize+header.TCPMinimumSize:], data; !bytes.Equal(got, want) {
t.Fatalf("got packet #%d's data = %v, want = %v", i+1, got, want)
}
seq = seq.Add(seqnum.Size(len(data)))
}
// Acknowledge the data.
c.SendPacket(nil, &context.Headers{
SrcPort: context.TestPort,
DstPort: c.Port,
Flags: header.TCPFlagAck,
SeqNum: 790,
AckNum: seq,
RcvWnd: 30000,
})
})
}
}
func testBrokenUpWrite(t *testing.T, c *context.Context, maxPayload int) {
payloadMultiplier := 10
dataLen := payloadMultiplier * maxPayload
data := make([]byte, dataLen)
for i := range data {
data[i] = byte(i)
}
view := buffer.NewView(len(data))
copy(view, data)
if _, _, err := c.EP.Write(tcpip.SlicePayload(view), tcpip.WriteOptions{}); err != nil {
t.Fatalf("Write failed: %v", err)
}
// Check that data is received in chunks.
bytesReceived := 0
numPackets := 0
for bytesReceived != dataLen {
b := c.GetPacket()
numPackets++
tcp := header.TCP(header.IPv4(b).Payload())
payloadLen := len(tcp.Payload())
checker.IPv4(t, b,
checker.TCP(
checker.DstPort(context.TestPort),
checker.SeqNum(uint32(c.IRS)+1+uint32(bytesReceived)),
checker.AckNum(790),
checker.TCPFlagsMatch(header.TCPFlagAck, ^uint8(header.TCPFlagPsh)),
),
)
pdata := data[bytesReceived : bytesReceived+payloadLen]
if p := tcp.Payload(); !bytes.Equal(pdata, p) {
t.Fatalf("got data = %v, want = %v", p, pdata)
}
bytesReceived += payloadLen
var options []byte
if c.TimeStampEnabled {
// If timestamp option is enabled, echo back the timestamp and increment
// the TSEcr value included in the packet and send that back as the TSVal.
parsedOpts := tcp.ParsedOptions()
tsOpt := [12]byte{header.TCPOptionNOP, header.TCPOptionNOP}
header.EncodeTSOption(parsedOpts.TSEcr+1, parsedOpts.TSVal, tsOpt[2:])
options = tsOpt[:]
}
// Acknowledge the data.
c.SendPacket(nil, &context.Headers{
SrcPort: context.TestPort,
DstPort: c.Port,
Flags: header.TCPFlagAck,
SeqNum: 790,
AckNum: c.IRS.Add(1 + seqnum.Size(bytesReceived)),
RcvWnd: 30000,
TCPOpts: options,
})
}
if numPackets == 1 {
t.Fatalf("expected write to be broken up into multiple packets, but got 1 packet")
}
}
func TestSendGreaterThanMTU(t *testing.T) {
const maxPayload = 100
c := context.New(t, uint32(header.TCPMinimumSize+header.IPv4MinimumSize+maxPayload))
defer c.Cleanup()
c.CreateConnected(789, 30000, nil)
testBrokenUpWrite(t, c, maxPayload)
}
func TestActiveSendMSSLessThanMTU(t *testing.T) {
const maxPayload = 100
c := context.New(t, 65535)
defer c.Cleanup()
c.CreateConnectedWithRawOptions(789, 30000, nil, []byte{
header.TCPOptionMSS, 4, byte(maxPayload / 256), byte(maxPayload % 256),
})
testBrokenUpWrite(t, c, maxPayload)
}
func TestPassiveSendMSSLessThanMTU(t *testing.T) {
const maxPayload = 100
const mtu = 1200
c := context.New(t, mtu)
defer c.Cleanup()
// Create EP and start listening.
wq := &waiter.Queue{}
ep, err := c.Stack().NewEndpoint(tcp.ProtocolNumber, ipv4.ProtocolNumber, wq)
if err != nil {
t.Fatalf("NewEndpoint failed: %v", err)
}
defer ep.Close()
// Set the buffer size to a deterministic size so that we can check the
// window scaling option.
const rcvBufferSize = 0x20000
const wndScale = 2
if err := ep.SetSockOpt(tcpip.ReceiveBufferSizeOption(rcvBufferSize)); err != nil {
t.Fatalf("SetSockOpt failed failed: %v", err)
}
if err := ep.Bind(tcpip.FullAddress{Port: context.StackPort}, nil); err != nil {
t.Fatalf("Bind failed: %v", err)
}
if err := ep.Listen(10); err != nil {
t.Fatalf("Listen failed: %v", err)
}
// Do 3-way handshake.
c.PassiveConnect(maxPayload, wndScale, header.TCPSynOptions{MSS: mtu - header.IPv4MinimumSize - header.TCPMinimumSize})
// Try to accept the connection.
we, ch := waiter.NewChannelEntry(nil)
wq.EventRegister(&we, waiter.EventIn)
defer wq.EventUnregister(&we)
c.EP, _, err = ep.Accept()
if err == tcpip.ErrWouldBlock {
// Wait for connection to be established.
select {
case <-ch:
c.EP, _, err = ep.Accept()
if err != nil {
t.Fatalf("Accept failed: %v", err)
}
case <-time.After(1 * time.Second):
t.Fatalf("Timed out waiting for accept")
}
}
// Check that data gets properly segmented.
testBrokenUpWrite(t, c, maxPayload)
}
func TestSynCookiePassiveSendMSSLessThanMTU(t *testing.T) {
const maxPayload = 536
const mtu = 2000
c := context.New(t, mtu)
defer c.Cleanup()
// Set the SynRcvd threshold to zero to force a syn cookie based accept
// to happen.
saved := tcp.SynRcvdCountThreshold
defer func() {
tcp.SynRcvdCountThreshold = saved
}()
tcp.SynRcvdCountThreshold = 0
// Create EP and start listening.
wq := &waiter.Queue{}
ep, err := c.Stack().NewEndpoint(tcp.ProtocolNumber, ipv4.ProtocolNumber, wq)
if err != nil {
t.Fatalf("NewEndpoint failed: %v", err)
}
defer ep.Close()
if err := ep.Bind(tcpip.FullAddress{Port: context.StackPort}, nil); err != nil {
t.Fatalf("Bind failed: %v", err)
}
if err := ep.Listen(10); err != nil {
t.Fatalf("Listen failed: %v", err)
}
// Do 3-way handshake.
c.PassiveConnect(maxPayload, -1, header.TCPSynOptions{MSS: mtu - header.IPv4MinimumSize - header.TCPMinimumSize})
// Try to accept the connection.
we, ch := waiter.NewChannelEntry(nil)
wq.EventRegister(&we, waiter.EventIn)
defer wq.EventUnregister(&we)
c.EP, _, err = ep.Accept()
if err == tcpip.ErrWouldBlock {
// Wait for connection to be established.
select {
case <-ch:
c.EP, _, err = ep.Accept()
if err != nil {
t.Fatalf("Accept failed: %v", err)
}
case <-time.After(1 * time.Second):
t.Fatalf("Timed out waiting for accept")
}
}
// Check that data gets properly segmented.
testBrokenUpWrite(t, c, maxPayload)
}
func TestForwarderSendMSSLessThanMTU(t *testing.T) {
const maxPayload = 100
const mtu = 1200
c := context.New(t, mtu)
defer c.Cleanup()
s := c.Stack()
ch := make(chan *tcpip.Error, 1)
f := tcp.NewForwarder(s, 65536, 10, func(r *tcp.ForwarderRequest) {
var err *tcpip.Error
c.EP, err = r.CreateEndpoint(&c.WQ)
ch <- err
})
s.SetTransportProtocolHandler(tcp.ProtocolNumber, f.HandlePacket)
// Do 3-way handshake.
c.PassiveConnect(maxPayload, 1, header.TCPSynOptions{MSS: mtu - header.IPv4MinimumSize - header.TCPMinimumSize})
// Wait for connection to be available.
select {
case err := <-ch:
if err != nil {
t.Fatalf("Error creating endpoint: %v", err)
}
case <-time.After(2 * time.Second):
t.Fatalf("Timed out waiting for connection")
}
// Check that data gets properly segmented.
testBrokenUpWrite(t, c, maxPayload)
}
func TestSynOptionsOnActiveConnect(t *testing.T) {
const mtu = 1400
c := context.New(t, mtu)
defer c.Cleanup()
// Create TCP endpoint.
var err *tcpip.Error
c.EP, err = c.Stack().NewEndpoint(tcp.ProtocolNumber, ipv4.ProtocolNumber, &c.WQ)
if err != nil {
t.Fatalf("NewEndpoint failed: %v", err)
}
// Set the buffer size to a deterministic size so that we can check the
// window scaling option.
const rcvBufferSize = 0x20000
const wndScale = 2
if err := c.EP.SetSockOpt(tcpip.ReceiveBufferSizeOption(rcvBufferSize)); err != nil {
t.Fatalf("SetSockOpt failed failed: %v", err)
}
// Start connection attempt.
we, ch := waiter.NewChannelEntry(nil)
c.WQ.EventRegister(&we, waiter.EventOut)
defer c.WQ.EventUnregister(&we)
if err := c.EP.Connect(tcpip.FullAddress{Addr: context.TestAddr, Port: context.TestPort}); err != tcpip.ErrConnectStarted {
t.Fatalf("got c.EP.Connect(...) = %v, want = %v", err, tcpip.ErrConnectStarted)
}
// Receive SYN packet.
b := c.GetPacket()
checker.IPv4(t, b,
checker.TCP(
checker.DstPort(context.TestPort),
checker.TCPFlags(header.TCPFlagSyn),
checker.TCPSynOptions(header.TCPSynOptions{MSS: mtu - header.IPv4MinimumSize - header.TCPMinimumSize, WS: wndScale}),
),
)
tcp := header.TCP(header.IPv4(b).Payload())
c.IRS = seqnum.Value(tcp.SequenceNumber())
// Wait for retransmit.
time.Sleep(1 * time.Second)
checker.IPv4(t, c.GetPacket(),
checker.TCP(
checker.DstPort(context.TestPort),
checker.TCPFlags(header.TCPFlagSyn),
checker.SrcPort(tcp.SourcePort()),
checker.SeqNum(tcp.SequenceNumber()),
checker.TCPSynOptions(header.TCPSynOptions{MSS: mtu - header.IPv4MinimumSize - header.TCPMinimumSize, WS: wndScale}),
),
)
// Send SYN-ACK.
iss := seqnum.Value(789)
c.SendPacket(nil, &context.Headers{
SrcPort: tcp.DestinationPort(),
DstPort: tcp.SourcePort(),
Flags: header.TCPFlagSyn | header.TCPFlagAck,
SeqNum: iss,
AckNum: c.IRS.Add(1),
RcvWnd: 30000,
})
// Receive ACK packet.
checker.IPv4(t, c.GetPacket(),
checker.TCP(
checker.DstPort(context.TestPort),
checker.TCPFlags(header.TCPFlagAck),
checker.SeqNum(uint32(c.IRS)+1),
checker.AckNum(uint32(iss)+1),
),
)
// Wait for connection to be established.
select {
case <-ch:
if err := c.EP.GetSockOpt(tcpip.ErrorOption{}); err != nil {
t.Fatalf("GetSockOpt failed: %v", err)
}
case <-time.After(1 * time.Second):
t.Fatalf("Timed out waiting for connection")
}
}
func TestCloseListener(t *testing.T) {
c := context.New(t, defaultMTU)
defer c.Cleanup()
// Create listener.
var wq waiter.Queue
ep, err := c.Stack().NewEndpoint(tcp.ProtocolNumber, ipv4.ProtocolNumber, &wq)
if err != nil {
t.Fatalf("NewEndpoint failed: %v", err)
}
if err := ep.Bind(tcpip.FullAddress{}, nil); err != nil {
t.Fatalf("Bind failed: %v", err)
}
if err := ep.Listen(10); err != nil {
t.Fatalf("Listen failed: %v", err)
}
// Close the listener and measure how long it takes.
t0 := time.Now()
ep.Close()
if diff := time.Now().Sub(t0); diff > 3*time.Second {
t.Fatalf("Took too long to close: %v", diff)
}
}
func TestReceiveOnResetConnection(t *testing.T) {
c := context.New(t, defaultMTU)
defer c.Cleanup()
c.CreateConnected(789, 30000, nil)
// Send RST segment.
c.SendPacket(nil, &context.Headers{
SrcPort: context.TestPort,
DstPort: c.Port,
Flags: header.TCPFlagRst,
SeqNum: 790,
RcvWnd: 30000,
})
// Try to read.
we, ch := waiter.NewChannelEntry(nil)
c.WQ.EventRegister(&we, waiter.EventIn)
defer c.WQ.EventUnregister(&we)
loop:
for {
switch _, _, err := c.EP.Read(nil); err {
case tcpip.ErrWouldBlock:
select {
case <-ch:
case <-time.After(1 * time.Second):
t.Fatalf("Timed out waiting for reset to arrive")
}
case tcpip.ErrConnectionReset:
break loop
default:
t.Fatalf("got c.EP.Read(nil) = %v, want = %v", err, tcpip.ErrConnectionReset)
}
}
}
func TestSendOnResetConnection(t *testing.T) {
c := context.New(t, defaultMTU)
defer c.Cleanup()
c.CreateConnected(789, 30000, nil)
// Send RST segment.
c.SendPacket(nil, &context.Headers{
SrcPort: context.TestPort,
DstPort: c.Port,
Flags: header.TCPFlagRst,
SeqNum: 790,
RcvWnd: 30000,
})
// Wait for the RST to be received.
time.Sleep(1 * time.Second)
// Try to write.
view := buffer.NewView(10)
if _, _, err := c.EP.Write(tcpip.SlicePayload(view), tcpip.WriteOptions{}); err != tcpip.ErrConnectionReset {
t.Fatalf("got c.EP.Write(...) = %v, want = %v", err, tcpip.ErrConnectionReset)
}
}
func TestFinImmediately(t *testing.T) {
c := context.New(t, defaultMTU)
defer c.Cleanup()
c.CreateConnected(789, 30000, nil)
// Shutdown immediately, check that we get a FIN.
if err := c.EP.Shutdown(tcpip.ShutdownWrite); err != nil {
t.Fatalf("Shutdown failed: %v", err)
}
checker.IPv4(t, c.GetPacket(),
checker.PayloadLen(header.TCPMinimumSize),
checker.TCP(
checker.DstPort(context.TestPort),
checker.SeqNum(uint32(c.IRS)+1),
checker.AckNum(790),
checker.TCPFlags(header.TCPFlagAck|header.TCPFlagFin),
),
)
// Ack and send FIN as well.
c.SendPacket(nil, &context.Headers{
SrcPort: context.TestPort,
DstPort: c.Port,
Flags: header.TCPFlagAck | header.TCPFlagFin,
SeqNum: 790,
AckNum: c.IRS.Add(2),
RcvWnd: 30000,
})
// Check that the stack acks the FIN.
checker.IPv4(t, c.GetPacket(),
checker.PayloadLen(header.TCPMinimumSize),
checker.TCP(
checker.DstPort(context.TestPort),
checker.SeqNum(uint32(c.IRS)+2),
checker.AckNum(791),
checker.TCPFlags(header.TCPFlagAck),
),
)
}
func TestFinRetransmit(t *testing.T) {
c := context.New(t, defaultMTU)
defer c.Cleanup()
c.CreateConnected(789, 30000, nil)
// Shutdown immediately, check that we get a FIN.
if err := c.EP.Shutdown(tcpip.ShutdownWrite); err != nil {
t.Fatalf("Shutdown failed: %v", err)
}
checker.IPv4(t, c.GetPacket(),
checker.PayloadLen(header.TCPMinimumSize),
checker.TCP(
checker.DstPort(context.TestPort),
checker.SeqNum(uint32(c.IRS)+1),
checker.AckNum(790),
checker.TCPFlags(header.TCPFlagAck|header.TCPFlagFin),
),
)
// Don't acknowledge yet. We should get a retransmit of the FIN.
checker.IPv4(t, c.GetPacket(),
checker.PayloadLen(header.TCPMinimumSize),
checker.TCP(
checker.DstPort(context.TestPort),
checker.SeqNum(uint32(c.IRS)+1),
checker.AckNum(790),
checker.TCPFlags(header.TCPFlagAck|header.TCPFlagFin),
),
)
// Ack and send FIN as well.
c.SendPacket(nil, &context.Headers{
SrcPort: context.TestPort,
DstPort: c.Port,
Flags: header.TCPFlagAck | header.TCPFlagFin,
SeqNum: 790,
AckNum: c.IRS.Add(2),
RcvWnd: 30000,
})
// Check that the stack acks the FIN.
checker.IPv4(t, c.GetPacket(),
checker.PayloadLen(header.TCPMinimumSize),
checker.TCP(
checker.DstPort(context.TestPort),
checker.SeqNum(uint32(c.IRS)+2),
checker.AckNum(791),
checker.TCPFlags(header.TCPFlagAck),
),
)
}
func TestFinWithNoPendingData(t *testing.T) {
c := context.New(t, defaultMTU)
defer c.Cleanup()
c.CreateConnected(789, 30000, nil)
// Write something out, and have it acknowledged.
view := buffer.NewView(10)
if _, _, err := c.EP.Write(tcpip.SlicePayload(view), tcpip.WriteOptions{}); err != nil {
t.Fatalf("Write failed: %v", err)
}
next := uint32(c.IRS) + 1
checker.IPv4(t, c.GetPacket(),
checker.PayloadLen(len(view)+header.TCPMinimumSize),
checker.TCP(
checker.DstPort(context.TestPort),
checker.SeqNum(next),
checker.AckNum(790),
checker.TCPFlagsMatch(header.TCPFlagAck, ^uint8(header.TCPFlagPsh)),
),
)
next += uint32(len(view))
c.SendPacket(nil, &context.Headers{
SrcPort: context.TestPort,
DstPort: c.Port,
Flags: header.TCPFlagAck,
SeqNum: 790,
AckNum: seqnum.Value(next),
RcvWnd: 30000,
})
// Shutdown, check that we get a FIN.
if err := c.EP.Shutdown(tcpip.ShutdownWrite); err != nil {
t.Fatalf("Shutdown failed: %v", err)
}
checker.IPv4(t, c.GetPacket(),
checker.PayloadLen(header.TCPMinimumSize),
checker.TCP(
checker.DstPort(context.TestPort),
checker.SeqNum(next),
checker.AckNum(790),
checker.TCPFlags(header.TCPFlagAck|header.TCPFlagFin),
),
)
next++
// Ack and send FIN as well.
c.SendPacket(nil, &context.Headers{
SrcPort: context.TestPort,
DstPort: c.Port,
Flags: header.TCPFlagAck | header.TCPFlagFin,
SeqNum: 790,
AckNum: seqnum.Value(next),
RcvWnd: 30000,
})
// Check that the stack acks the FIN.
checker.IPv4(t, c.GetPacket(),
checker.PayloadLen(header.TCPMinimumSize),
checker.TCP(
checker.DstPort(context.TestPort),
checker.SeqNum(next),
checker.AckNum(791),
checker.TCPFlags(header.TCPFlagAck),
),
)
}
func TestFinWithPendingDataCwndFull(t *testing.T) {
c := context.New(t, defaultMTU)
defer c.Cleanup()
c.CreateConnected(789, 30000, nil)
// Write enough segments to fill the congestion window before ACK'ing
// any of them.
view := buffer.NewView(10)
for i := tcp.InitialCwnd; i > 0; i-- {
if _, _, err := c.EP.Write(tcpip.SlicePayload(view), tcpip.WriteOptions{}); err != nil {
t.Fatalf("Write failed: %v", err)
}
}
next := uint32(c.IRS) + 1
for i := tcp.InitialCwnd; i > 0; i-- {
checker.IPv4(t, c.GetPacket(),
checker.PayloadLen(len(view)+header.TCPMinimumSize),
checker.TCP(
checker.DstPort(context.TestPort),
checker.SeqNum(next),
checker.AckNum(790),
checker.TCPFlagsMatch(header.TCPFlagAck, ^uint8(header.TCPFlagPsh)),
),
)
next += uint32(len(view))
}
// Shutdown the connection, check that the FIN segment isn't sent
// because the congestion window doesn't allow it. Wait until a
// retransmit is received.
if err := c.EP.Shutdown(tcpip.ShutdownWrite); err != nil {
t.Fatalf("Shutdown failed: %v", err)
}
checker.IPv4(t, c.GetPacket(),
checker.PayloadLen(len(view)+header.TCPMinimumSize),
checker.TCP(
checker.DstPort(context.TestPort),
checker.SeqNum(uint32(c.IRS)+1),
checker.AckNum(790),
checker.TCPFlagsMatch(header.TCPFlagAck, ^uint8(header.TCPFlagPsh)),
),
)
// Send the ACK that will allow the FIN to be sent as well.
c.SendPacket(nil, &context.Headers{
SrcPort: context.TestPort,
DstPort: c.Port,
Flags: header.TCPFlagAck,
SeqNum: 790,
AckNum: seqnum.Value(next),
RcvWnd: 30000,
})
checker.IPv4(t, c.GetPacket(),
checker.PayloadLen(header.TCPMinimumSize),
checker.TCP(
checker.DstPort(context.TestPort),
checker.SeqNum(next),
checker.AckNum(790),
checker.TCPFlags(header.TCPFlagAck|header.TCPFlagFin),
),
)
next++
// Send a FIN that acknowledges everything. Get an ACK back.
c.SendPacket(nil, &context.Headers{
SrcPort: context.TestPort,
DstPort: c.Port,
Flags: header.TCPFlagAck | header.TCPFlagFin,
SeqNum: 790,
AckNum: seqnum.Value(next),
RcvWnd: 30000,
})
checker.IPv4(t, c.GetPacket(),
checker.PayloadLen(header.TCPMinimumSize),
checker.TCP(
checker.DstPort(context.TestPort),
checker.SeqNum(next),
checker.AckNum(791),
checker.TCPFlags(header.TCPFlagAck),
),
)
}
func TestFinWithPendingData(t *testing.T) {
c := context.New(t, defaultMTU)
defer c.Cleanup()
c.CreateConnected(789, 30000, nil)
// Write something out, and acknowledge it to get cwnd to 2.
view := buffer.NewView(10)
if _, _, err := c.EP.Write(tcpip.SlicePayload(view), tcpip.WriteOptions{}); err != nil {
t.Fatalf("Write failed: %v", err)
}
next := uint32(c.IRS) + 1
checker.IPv4(t, c.GetPacket(),
checker.PayloadLen(len(view)+header.TCPMinimumSize),
checker.TCP(
checker.DstPort(context.TestPort),
checker.SeqNum(next),
checker.AckNum(790),
checker.TCPFlagsMatch(header.TCPFlagAck, ^uint8(header.TCPFlagPsh)),
),
)
next += uint32(len(view))
c.SendPacket(nil, &context.Headers{
SrcPort: context.TestPort,
DstPort: c.Port,
Flags: header.TCPFlagAck,
SeqNum: 790,
AckNum: seqnum.Value(next),
RcvWnd: 30000,
})
// Write new data, but don't acknowledge it.
if _, _, err := c.EP.Write(tcpip.SlicePayload(view), tcpip.WriteOptions{}); err != nil {
t.Fatalf("Write failed: %v", err)
}
checker.IPv4(t, c.GetPacket(),
checker.PayloadLen(len(view)+header.TCPMinimumSize),
checker.TCP(
checker.DstPort(context.TestPort),
checker.SeqNum(next),
checker.AckNum(790),
checker.TCPFlagsMatch(header.TCPFlagAck, ^uint8(header.TCPFlagPsh)),
),
)
next += uint32(len(view))
// Shutdown the connection, check that we do get a FIN.
if err := c.EP.Shutdown(tcpip.ShutdownWrite); err != nil {
t.Fatalf("Shutdown failed: %v", err)
}
checker.IPv4(t, c.GetPacket(),
checker.PayloadLen(header.TCPMinimumSize),
checker.TCP(
checker.DstPort(context.TestPort),
checker.SeqNum(next),
checker.AckNum(790),
checker.TCPFlags(header.TCPFlagAck|header.TCPFlagFin),
),
)
next++
// Send a FIN that acknowledges everything. Get an ACK back.
c.SendPacket(nil, &context.Headers{
SrcPort: context.TestPort,
DstPort: c.Port,
Flags: header.TCPFlagAck | header.TCPFlagFin,
SeqNum: 790,
AckNum: seqnum.Value(next),
RcvWnd: 30000,
})
checker.IPv4(t, c.GetPacket(),
checker.PayloadLen(header.TCPMinimumSize),
checker.TCP(
checker.DstPort(context.TestPort),
checker.SeqNum(next),
checker.AckNum(791),
checker.TCPFlags(header.TCPFlagAck),
),
)
}
func TestFinWithPartialAck(t *testing.T) {
c := context.New(t, defaultMTU)
defer c.Cleanup()
c.CreateConnected(789, 30000, nil)
// Write something out, and acknowledge it to get cwnd to 2. Also send
// FIN from the test side.
view := buffer.NewView(10)
if _, _, err := c.EP.Write(tcpip.SlicePayload(view), tcpip.WriteOptions{}); err != nil {
t.Fatalf("Write failed: %v", err)
}
next := uint32(c.IRS) + 1
checker.IPv4(t, c.GetPacket(),
checker.PayloadLen(len(view)+header.TCPMinimumSize),
checker.TCP(
checker.DstPort(context.TestPort),
checker.SeqNum(next),
checker.AckNum(790),
checker.TCPFlagsMatch(header.TCPFlagAck, ^uint8(header.TCPFlagPsh)),
),
)
next += uint32(len(view))
c.SendPacket(nil, &context.Headers{
SrcPort: context.TestPort,
DstPort: c.Port,
Flags: header.TCPFlagAck | header.TCPFlagFin,
SeqNum: 790,
AckNum: seqnum.Value(next),
RcvWnd: 30000,
})
// Check that we get an ACK for the fin.
checker.IPv4(t, c.GetPacket(),
checker.PayloadLen(header.TCPMinimumSize),
checker.TCP(
checker.DstPort(context.TestPort),
checker.SeqNum(next),
checker.AckNum(791),
checker.TCPFlagsMatch(header.TCPFlagAck, ^uint8(header.TCPFlagPsh)),
),
)
// Write new data, but don't acknowledge it.
if _, _, err := c.EP.Write(tcpip.SlicePayload(view), tcpip.WriteOptions{}); err != nil {
t.Fatalf("Write failed: %v", err)
}
checker.IPv4(t, c.GetPacket(),
checker.PayloadLen(len(view)+header.TCPMinimumSize),
checker.TCP(
checker.DstPort(context.TestPort),
checker.SeqNum(next),
checker.AckNum(791),
checker.TCPFlagsMatch(header.TCPFlagAck, ^uint8(header.TCPFlagPsh)),
),
)
next += uint32(len(view))
// Shutdown the connection, check that we do get a FIN.
if err := c.EP.Shutdown(tcpip.ShutdownWrite); err != nil {
t.Fatalf("Shutdown failed: %v", err)
}
checker.IPv4(t, c.GetPacket(),
checker.PayloadLen(header.TCPMinimumSize),
checker.TCP(
checker.DstPort(context.TestPort),
checker.SeqNum(next),
checker.AckNum(791),
checker.TCPFlags(header.TCPFlagAck|header.TCPFlagFin),
),
)
next++
// Send an ACK for the data, but not for the FIN yet.
c.SendPacket(nil, &context.Headers{
SrcPort: context.TestPort,
DstPort: c.Port,
Flags: header.TCPFlagAck,
SeqNum: 791,
AckNum: seqnum.Value(next - 1),
RcvWnd: 30000,
})
// Check that we don't get a retransmit of the FIN.
c.CheckNoPacketTimeout("FIN retransmitted when data was ack'd", 100*time.Millisecond)
// Ack the FIN.
c.SendPacket(nil, &context.Headers{
SrcPort: context.TestPort,
DstPort: c.Port,
Flags: header.TCPFlagAck | header.TCPFlagFin,
SeqNum: 791,
AckNum: seqnum.Value(next),
RcvWnd: 30000,
})
}
func TestExponentialIncreaseDuringSlowStart(t *testing.T) {
maxPayload := 10
c := context.New(t, uint32(header.TCPMinimumSize+header.IPv4MinimumSize+maxPayload))
defer c.Cleanup()
c.CreateConnected(789, 30000, nil)
const iterations = 7
data := buffer.NewView(maxPayload * (tcp.InitialCwnd << (iterations + 1)))
for i := range data {
data[i] = byte(i)
}
// Write all the data in one shot. Packets will only be written at the
// MTU size though.
if _, _, err := c.EP.Write(tcpip.SlicePayload(data), tcpip.WriteOptions{}); err != nil {
t.Fatalf("Write failed: %v", err)
}
expected := tcp.InitialCwnd
bytesRead := 0
for i := 0; i < iterations; i++ {
// Read all packets expected on this iteration. Don't
// acknowledge any of them just yet, so that we can measure the
// congestion window.
for j := 0; j < expected; j++ {
c.ReceiveAndCheckPacket(data, bytesRead, maxPayload)
bytesRead += maxPayload
}
// Check we don't receive any more packets on this iteration.
// The timeout can't be too high or we'll trigger a timeout.
c.CheckNoPacketTimeout("More packets received than expected for this cwnd.", 50*time.Millisecond)
// Acknowledge all the data received so far.
c.SendAck(790, bytesRead)
// Double the number of expected packets for the next iteration.
expected *= 2
}
}
func TestCongestionAvoidance(t *testing.T) {
maxPayload := 10
c := context.New(t, uint32(header.TCPMinimumSize+header.IPv4MinimumSize+maxPayload))
defer c.Cleanup()
c.CreateConnected(789, 30000, nil)
const iterations = 7
data := buffer.NewView(2 * maxPayload * (tcp.InitialCwnd << (iterations + 1)))
for i := range data {
data[i] = byte(i)
}
// Write all the data in one shot. Packets will only be written at the
// MTU size though.
if _, _, err := c.EP.Write(tcpip.SlicePayload(data), tcpip.WriteOptions{}); err != nil {
t.Fatalf("Write failed: %v", err)
}
// Do slow start for a few iterations.
expected := tcp.InitialCwnd
bytesRead := 0
for i := 0; i < iterations; i++ {
expected = tcp.InitialCwnd << uint(i)
if i > 0 {
// Acknowledge all the data received so far if not on
// first iteration.
c.SendAck(790, bytesRead)
}
// Read all packets expected on this iteration. Don't
// acknowledge any of them just yet, so that we can measure the
// congestion window.
for j := 0; j < expected; j++ {
c.ReceiveAndCheckPacket(data, bytesRead, maxPayload)
bytesRead += maxPayload
}
// Check we don't receive any more packets on this iteration.
// The timeout can't be too high or we'll trigger a timeout.
c.CheckNoPacketTimeout("More packets received than expected for this cwnd (slow start phase).", 50*time.Millisecond)
}
// Don't acknowledge the first packet of the last packet train. Let's
// wait for them to time out, which will trigger a restart of slow
// start, and initialization of ssthresh to cwnd/2.
rtxOffset := bytesRead - maxPayload*expected
c.ReceiveAndCheckPacket(data, rtxOffset, maxPayload)
// Acknowledge all the data received so far.
c.SendAck(790, bytesRead)
// This part is tricky: when the timeout happened, we had "expected"
// packets pending, cwnd reset to 1, and ssthresh set to expected/2.
// By acknowledging "expected" packets, the slow-start part will
// increase cwnd to expected/2 (which "consumes" expected/2-1 of the
// acknowledgements), then the congestion avoidance part will consume
// an extra expected/2 acks to take cwnd to expected/2 + 1. One ack
// remains in the "ack count" (which will cause cwnd to be incremented
// once it reaches cwnd acks).
//
// So we're straight into congestion avoidance with cwnd set to
// expected/2 + 1.
//
// Check that packets trains of cwnd packets are sent, and that cwnd is
// incremented by 1 after we acknowledge each packet.
expected = expected/2 + 1
for i := 0; i < iterations; i++ {
// Read all packets expected on this iteration. Don't
// acknowledge any of them just yet, so that we can measure the
// congestion window.
for j := 0; j < expected; j++ {
c.ReceiveAndCheckPacket(data, bytesRead, maxPayload)
bytesRead += maxPayload
}
// Check we don't receive any more packets on this iteration.
// The timeout can't be too high or we'll trigger a timeout.
c.CheckNoPacketTimeout("More packets received than expected for this cwnd (congestion avoidance phase).", 50*time.Millisecond)
// Acknowledge all the data received so far.
c.SendAck(790, bytesRead)
// In cogestion avoidance, the packets trains increase by 1 in
// each iteration.
expected++
}
}
// cubicCwnd returns an estimate of a cubic window given the
// originalCwnd, wMax, last congestion event time and sRTT.
func cubicCwnd(origCwnd int, wMax int, congEventTime time.Time, sRTT time.Duration) int {
cwnd := float64(origCwnd)
// We wait 50ms between each iteration so sRTT as computed by cubic
// should be close to 50ms.
elapsed := (time.Since(congEventTime) + sRTT).Seconds()
k := math.Cbrt(float64(wMax) * 0.3 / 0.7)
wtRTT := 0.4*math.Pow(elapsed-k, 3) + float64(wMax)
cwnd += (wtRTT - cwnd) / cwnd
return int(cwnd)
}
func TestCubicCongestionAvoidance(t *testing.T) {
maxPayload := 10
c := context.New(t, uint32(header.TCPMinimumSize+header.IPv4MinimumSize+maxPayload))
defer c.Cleanup()
enableCUBIC(t, c)
c.CreateConnected(789, 30000, nil)
const iterations = 7
data := buffer.NewView(2 * maxPayload * (tcp.InitialCwnd << (iterations + 1)))
for i := range data {
data[i] = byte(i)
}
// Write all the data in one shot. Packets will only be written at the
// MTU size though.
if _, _, err := c.EP.Write(tcpip.SlicePayload(data), tcpip.WriteOptions{}); err != nil {
t.Fatalf("Write failed: %v", err)
}
// Do slow start for a few iterations.
expected := tcp.InitialCwnd
bytesRead := 0
for i := 0; i < iterations; i++ {
expected = tcp.InitialCwnd << uint(i)
if i > 0 {
// Acknowledge all the data received so far if not on
// first iteration.
c.SendAck(790, bytesRead)
}
// Read all packets expected on this iteration. Don't
// acknowledge any of them just yet, so that we can measure the
// congestion window.
for j := 0; j < expected; j++ {
c.ReceiveAndCheckPacket(data, bytesRead, maxPayload)
bytesRead += maxPayload
}
// Check we don't receive any more packets on this iteration.
// The timeout can't be too high or we'll trigger a timeout.
c.CheckNoPacketTimeout("More packets received than expected for this cwnd (during slow-start phase).", 50*time.Millisecond)
}
// Don't acknowledge the first packet of the last packet train. Let's
// wait for them to time out, which will trigger a restart of slow
// start, and initialization of ssthresh to cwnd * 0.7.
rtxOffset := bytesRead - maxPayload*expected
c.ReceiveAndCheckPacket(data, rtxOffset, maxPayload)
// Acknowledge all pending data.
c.SendAck(790, bytesRead)
// Store away the time we sent the ACK and assuming a 200ms RTO
// we estimate that the sender will have an RTO 200ms from now
// and go back into slow start.
packetDropTime := time.Now().Add(200 * time.Millisecond)
// This part is tricky: when the timeout happened, we had "expected"
// packets pending, cwnd reset to 1, and ssthresh set to expected * 0.7.
// By acknowledging "expected" packets, the slow-start part will
// increase cwnd to expected/2 essentially putting the connection
// straight into congestion avoidance.
wMax := expected
// Lower expected as per cubic spec after a congestion event.
expected = int(float64(expected) * 0.7)
cwnd := expected
for i := 0; i < iterations; i++ {
// Cubic grows window independent of ACKs. Cubic Window growth
// is a function of time elapsed since last congestion event.
// As a result the congestion window does not grow
// deterministically in response to ACKs.
//
// We need to roughly estimate what the cwnd of the sender is
// based on when we sent the dupacks.
cwnd := cubicCwnd(cwnd, wMax, packetDropTime, 50*time.Millisecond)
packetsExpected := cwnd
for j := 0; j < packetsExpected; j++ {
c.ReceiveAndCheckPacket(data, bytesRead, maxPayload)
bytesRead += maxPayload
}
t.Logf("expected packets received, next trying to receive any extra packets that may come")
// If our estimate was correct there should be no more pending packets.
// We attempt to read a packet a few times with a short sleep in between
// to ensure that we don't see the sender send any unexpected packets.
unexpectedPackets := 0
for {
gotPacket := c.ReceiveNonBlockingAndCheckPacket(data, bytesRead, maxPayload)
if !gotPacket {
break
}
bytesRead += maxPayload
unexpectedPackets++
time.Sleep(1 * time.Millisecond)
}
if unexpectedPackets != 0 {
t.Fatalf("received %d unexpected packets for iteration %d", unexpectedPackets, i)
}
// Check we don't receive any more packets on this iteration.
// The timeout can't be too high or we'll trigger a timeout.
c.CheckNoPacketTimeout("More packets received than expected for this cwnd(congestion avoidance)", 5*time.Millisecond)
// Acknowledge all the data received so far.
c.SendAck(790, bytesRead)
}
}
func TestFastRecovery(t *testing.T) {
maxPayload := 10
c := context.New(t, uint32(header.TCPMinimumSize+header.IPv4MinimumSize+maxPayload))
defer c.Cleanup()
c.CreateConnected(789, 30000, nil)
const iterations = 7
data := buffer.NewView(2 * maxPayload * (tcp.InitialCwnd << (iterations + 1)))
for i := range data {
data[i] = byte(i)
}
// Write all the data in one shot. Packets will only be written at the
// MTU size though.
if _, _, err := c.EP.Write(tcpip.SlicePayload(data), tcpip.WriteOptions{}); err != nil {
t.Fatalf("Write failed: %v", err)
}
// Do slow start for a few iterations.
expected := tcp.InitialCwnd
bytesRead := 0
for i := 0; i < iterations; i++ {
expected = tcp.InitialCwnd << uint(i)
if i > 0 {
// Acknowledge all the data received so far if not on
// first iteration.
c.SendAck(790, bytesRead)
}
// Read all packets expected on this iteration. Don't
// acknowledge any of them just yet, so that we can measure the
// congestion window.
for j := 0; j < expected; j++ {
c.ReceiveAndCheckPacket(data, bytesRead, maxPayload)
bytesRead += maxPayload
}
// Check we don't receive any more packets on this iteration.
// The timeout can't be too high or we'll trigger a timeout.
c.CheckNoPacketTimeout("More packets received than expected for this cwnd.", 50*time.Millisecond)
}
// Send 3 duplicate acks. This should force an immediate retransmit of
// the pending packet and put the sender into fast recovery.
rtxOffset := bytesRead - maxPayload*expected
for i := 0; i < 3; i++ {
c.SendAck(790, rtxOffset)
}
// Receive the retransmitted packet.
c.ReceiveAndCheckPacket(data, rtxOffset, maxPayload)
// Now send 7 mode duplicate acks. Each of these should cause a window
// inflation by 1 and cause the sender to send an extra packet.
for i := 0; i < 7; i++ {
c.SendAck(790, rtxOffset)
}
recover := bytesRead
// Ensure no new packets arrive.
c.CheckNoPacketTimeout("More packets received than expected during recovery after dupacks for this cwnd.",
50*time.Millisecond)
// Acknowledge half of the pending data.
rtxOffset = bytesRead - expected*maxPayload/2
c.SendAck(790, rtxOffset)
// Receive the retransmit due to partial ack.
c.ReceiveAndCheckPacket(data, rtxOffset, maxPayload)
// Receive the 10 extra packets that should have been released due to
// the congestion window inflation in recovery.
for i := 0; i < 10; i++ {
c.ReceiveAndCheckPacket(data, bytesRead, maxPayload)
bytesRead += maxPayload
}
// A partial ACK during recovery should reduce congestion window by the
// number acked. Since we had "expected" packets outstanding before sending
// partial ack and we acked expected/2 , the cwnd and outstanding should
// be expected/2 + 7. Which means the sender should not send any more packets
// till we ack this one.
c.CheckNoPacketTimeout("More packets received than expected during recovery after partial ack for this cwnd.",
50*time.Millisecond)
// Acknowledge all pending data to recover point.
c.SendAck(790, recover)
// At this point, the cwnd should reset to expected/2 and there are 10
// packets outstanding.
//
// NOTE: Technically netstack is incorrect in that we adjust the cwnd on
// the same segment that takes us out of recovery. But because of that
// the actual cwnd at exit of recovery will be expected/2 + 1 as we
// acked a cwnd worth of packets which will increase the cwnd further by
// 1 in congestion avoidance.
//
// Now in the first iteration since there are 10 packets outstanding.
// We would expect to get expected/2 +1 - 10 packets. But subsequent
// iterations will send us expected/2 + 1 + 1 (per iteration).
expected = expected/2 + 1 - 10
for i := 0; i < iterations; i++ {
// Read all packets expected on this iteration. Don't
// acknowledge any of them just yet, so that we can measure the
// congestion window.
for j := 0; j < expected; j++ {
c.ReceiveAndCheckPacket(data, bytesRead, maxPayload)
bytesRead += maxPayload
}
// Check we don't receive any more packets on this iteration.
// The timeout can't be too high or we'll trigger a timeout.
c.CheckNoPacketTimeout(fmt.Sprintf("More packets received(after deflation) than expected %d for this cwnd.", expected), 50*time.Millisecond)
// Acknowledge all the data received so far.
c.SendAck(790, bytesRead)
// In cogestion avoidance, the packets trains increase by 1 in
// each iteration.
if i == 0 {
// After the first iteration we expect to get the full
// congestion window worth of packets in every
// iteration.
expected += 10
}
expected++
}
}
func TestRetransmit(t *testing.T) {
maxPayload := 10
c := context.New(t, uint32(header.TCPMinimumSize+header.IPv4MinimumSize+maxPayload))
defer c.Cleanup()
c.CreateConnected(789, 30000, nil)
const iterations = 7
data := buffer.NewView(maxPayload * (tcp.InitialCwnd << (iterations + 1)))
for i := range data {
data[i] = byte(i)
}
// Write all the data in two shots. Packets will only be written at the
// MTU size though.
half := data[:len(data)/2]
if _, _, err := c.EP.Write(tcpip.SlicePayload(half), tcpip.WriteOptions{}); err != nil {
t.Fatalf("Write failed: %v", err)
}
half = data[len(data)/2:]
if _, _, err := c.EP.Write(tcpip.SlicePayload(half), tcpip.WriteOptions{}); err != nil {
t.Fatalf("Write failed: %v", err)
}
// Do slow start for a few iterations.
expected := tcp.InitialCwnd
bytesRead := 0
for i := 0; i < iterations; i++ {
expected = tcp.InitialCwnd << uint(i)
if i > 0 {
// Acknowledge all the data received so far if not on
// first iteration.
c.SendAck(790, bytesRead)
}
// Read all packets expected on this iteration. Don't
// acknowledge any of them just yet, so that we can measure the
// congestion window.
for j := 0; j < expected; j++ {
c.ReceiveAndCheckPacket(data, bytesRead, maxPayload)
bytesRead += maxPayload
}
// Check we don't receive any more packets on this iteration.
// The timeout can't be too high or we'll trigger a timeout.
c.CheckNoPacketTimeout("More packets received than expected for this cwnd.", 50*time.Millisecond)
}
// Wait for a timeout and retransmit.
rtxOffset := bytesRead - maxPayload*expected
c.ReceiveAndCheckPacket(data, rtxOffset, maxPayload)
// Acknowledge half of the pending data.
rtxOffset = bytesRead - expected*maxPayload/2
c.SendAck(790, rtxOffset)
// Receive the remaining data, making sure that acknowledged data is not
// retransmitted.
for offset := rtxOffset; offset < len(data); offset += maxPayload {
c.ReceiveAndCheckPacket(data, offset, maxPayload)
c.SendAck(790, offset+maxPayload)
}
c.CheckNoPacketTimeout("More packets received than expected for this cwnd.", 50*time.Millisecond)
}
func TestUpdateListenBacklog(t *testing.T) {
c := context.New(t, defaultMTU)
defer c.Cleanup()
// Create listener.
var wq waiter.Queue
ep, err := c.Stack().NewEndpoint(tcp.ProtocolNumber, ipv4.ProtocolNumber, &wq)
if err != nil {
t.Fatalf("NewEndpoint failed: %v", err)
}
if err := ep.Bind(tcpip.FullAddress{}, nil); err != nil {
t.Fatalf("Bind failed: %v", err)
}
if err := ep.Listen(10); err != nil {
t.Fatalf("Listen failed: %v", err)
}
// Update the backlog with another Listen() on the same endpoint.
if err := ep.Listen(20); err != nil {
t.Fatalf("Listen failed to update backlog: %v", err)
}
ep.Close()
}
func scaledSendWindow(t *testing.T, scale uint8) {
// This test ensures that the endpoint is using the right scaling by
// sending a buffer that is larger than the window size, and ensuring
// that the endpoint doesn't send more than allowed.
c := context.New(t, defaultMTU)
defer c.Cleanup()
maxPayload := defaultMTU - header.IPv4MinimumSize - header.TCPMinimumSize
c.CreateConnectedWithRawOptions(789, 0, nil, []byte{
header.TCPOptionMSS, 4, byte(maxPayload / 256), byte(maxPayload % 256),
header.TCPOptionWS, 3, scale, header.TCPOptionNOP,
})
// Open up the window with a scaled value.
c.SendPacket(nil, &context.Headers{
SrcPort: context.TestPort,
DstPort: c.Port,
Flags: header.TCPFlagAck,
SeqNum: 790,
AckNum: c.IRS.Add(1),
RcvWnd: 1,
})
// Send some data. Check that it's capped by the window size.
view := buffer.NewView(65535)
if _, _, err := c.EP.Write(tcpip.SlicePayload(view), tcpip.WriteOptions{}); err != nil {
t.Fatalf("Write failed: %v", err)
}
// Check that only data that fits in the scaled window is sent.
checker.IPv4(t, c.GetPacket(),
checker.PayloadLen((1<<scale)+header.TCPMinimumSize),
checker.TCP(
checker.DstPort(context.TestPort),
checker.SeqNum(uint32(c.IRS)+1),
checker.AckNum(790),
checker.TCPFlagsMatch(header.TCPFlagAck, ^uint8(header.TCPFlagPsh)),
),
)
// Reset the connection to free resources.
c.SendPacket(nil, &context.Headers{
SrcPort: context.TestPort,
DstPort: c.Port,
Flags: header.TCPFlagRst,
SeqNum: 790,
})
}
func TestScaledSendWindow(t *testing.T) {
for scale := uint8(0); scale <= 14; scale++ {
scaledSendWindow(t, scale)
}
}
func TestReceivedValidSegmentCountIncrement(t *testing.T) {
c := context.New(t, defaultMTU)
defer c.Cleanup()
c.CreateConnected(789, 30000, nil)
stats := c.Stack().Stats()
want := stats.TCP.ValidSegmentsReceived.Value() + 1
c.SendPacket(nil, &context.Headers{
SrcPort: context.TestPort,
DstPort: c.Port,
Flags: header.TCPFlagAck,
SeqNum: seqnum.Value(790),
AckNum: c.IRS.Add(1),
RcvWnd: 30000,
})
if got := stats.TCP.ValidSegmentsReceived.Value(); got != want {
t.Errorf("got stats.TCP.ValidSegmentsReceived.Value() = %v, want = %v", got, want)
}
}
func TestReceivedInvalidSegmentCountIncrement(t *testing.T) {
c := context.New(t, defaultMTU)
defer c.Cleanup()
c.CreateConnected(789, 30000, nil)
stats := c.Stack().Stats()
want := stats.TCP.InvalidSegmentsReceived.Value() + 1
vv := c.BuildSegment(nil, &context.Headers{
SrcPort: context.TestPort,
DstPort: c.Port,
Flags: header.TCPFlagAck,
SeqNum: seqnum.Value(790),
AckNum: c.IRS.Add(1),
RcvWnd: 30000,
})
tcpbuf := vv.First()[header.IPv4MinimumSize:]
// 12 is the TCP header data offset.
tcpbuf[12] = ((header.TCPMinimumSize - 1) / 4) << 4
c.SendSegment(vv)
if got := stats.TCP.InvalidSegmentsReceived.Value(); got != want {
t.Errorf("got stats.TCP.InvalidSegmentsReceived.Value() = %v, want = %v", got, want)
}
}
func TestReceivedSegmentQueuing(t *testing.T) {
// This test sends 200 segments containing a few bytes each to an
// endpoint and checks that they're all received and acknowledged by
// the endpoint, that is, that none of the segments are dropped by
// internal queues.
c := context.New(t, defaultMTU)
defer c.Cleanup()
c.CreateConnected(789, 30000, nil)
// Send 200 segments.
data := []byte{1, 2, 3}
for i := 0; i < 200; i++ {
c.SendPacket(data, &context.Headers{
SrcPort: context.TestPort,
DstPort: c.Port,
Flags: header.TCPFlagAck,
SeqNum: seqnum.Value(790 + i*len(data)),
AckNum: c.IRS.Add(1),
RcvWnd: 30000,
})
}
// Receive ACKs for all segments.
last := seqnum.Value(790 + 200*len(data))
for {
b := c.GetPacket()
checker.IPv4(t, b,
checker.TCP(
checker.DstPort(context.TestPort),
checker.SeqNum(uint32(c.IRS)+1),
checker.TCPFlags(header.TCPFlagAck),
),
)
tcp := header.TCP(header.IPv4(b).Payload())
ack := seqnum.Value(tcp.AckNumber())
if ack == last {
break
}
if last.LessThan(ack) {
t.Fatalf("Acknowledge (%v) beyond the expected (%v)", ack, last)
}
}
}
func TestReadAfterClosedState(t *testing.T) {
// This test ensures that calling Read() or Peek() after the endpoint
// has transitioned to closedState still works if there is pending
// data. To transition to stateClosed without calling Close(), we must
// shutdown the send path and the peer must send its own FIN.
c := context.New(t, defaultMTU)
defer c.Cleanup()
c.CreateConnected(789, 30000, nil)
we, ch := waiter.NewChannelEntry(nil)
c.WQ.EventRegister(&we, waiter.EventIn)
defer c.WQ.EventUnregister(&we)
if _, _, err := c.EP.Read(nil); err != tcpip.ErrWouldBlock {
t.Fatalf("got c.EP.Read(nil) = %v, want = %v", err, tcpip.ErrWouldBlock)
}
// Shutdown immediately for write, check that we get a FIN.
if err := c.EP.Shutdown(tcpip.ShutdownWrite); err != nil {
t.Fatalf("Shutdown failed: %v", err)
}
checker.IPv4(t, c.GetPacket(),
checker.PayloadLen(header.TCPMinimumSize),
checker.TCP(
checker.DstPort(context.TestPort),
checker.SeqNum(uint32(c.IRS)+1),
checker.AckNum(790),
checker.TCPFlags(header.TCPFlagAck|header.TCPFlagFin),
),
)
// Send some data and acknowledge the FIN.
data := []byte{1, 2, 3}
c.SendPacket(data, &context.Headers{
SrcPort: context.TestPort,
DstPort: c.Port,
Flags: header.TCPFlagAck | header.TCPFlagFin,
SeqNum: 790,
AckNum: c.IRS.Add(2),
RcvWnd: 30000,
})
// Check that ACK is received.
checker.IPv4(t, c.GetPacket(),
checker.TCP(
checker.DstPort(context.TestPort),
checker.SeqNum(uint32(c.IRS)+2),
checker.AckNum(uint32(791+len(data))),
checker.TCPFlags(header.TCPFlagAck),
),
)
// Give the stack the chance to transition to closed state.
time.Sleep(1 * time.Second)
// Wait for receive to be notified.
select {
case <-ch:
case <-time.After(1 * time.Second):
t.Fatalf("Timed out waiting for data to arrive")
}
// Check that peek works.
peekBuf := make([]byte, 10)
n, _, err := c.EP.Peek([][]byte{peekBuf})
if err != nil {
t.Fatalf("Peek failed: %v", err)
}
peekBuf = peekBuf[:n]
if !bytes.Equal(data, peekBuf) {
t.Fatalf("got data = %v, want = %v", peekBuf, data)
}
// Receive data.
v, _, err := c.EP.Read(nil)
if err != nil {
t.Fatalf("Read failed: %v", err)
}
if !bytes.Equal(data, v) {
t.Fatalf("got data = %v, want = %v", v, data)
}
// Now that we drained the queue, check that functions fail with the
// right error code.
if _, _, err := c.EP.Read(nil); err != tcpip.ErrClosedForReceive {
t.Fatalf("got c.EP.Read(nil) = %v, want = %v", err, tcpip.ErrClosedForReceive)
}
if _, _, err := c.EP.Peek([][]byte{peekBuf}); err != tcpip.ErrClosedForReceive {
t.Fatalf("got c.EP.Peek(...) = %v, want = %v", err, tcpip.ErrClosedForReceive)
}
}
func TestReusePort(t *testing.T) {
// This test ensures that ports are immediately available for reuse
// after Close on the endpoints using them returns.
c := context.New(t, defaultMTU)
defer c.Cleanup()
// First case, just an endpoint that was bound.
var err *tcpip.Error
c.EP, err = c.Stack().NewEndpoint(tcp.ProtocolNumber, ipv4.ProtocolNumber, &waiter.Queue{})
if err != nil {
t.Fatalf("NewEndpoint failed; %v", err)
}
if err := c.EP.Bind(tcpip.FullAddress{Port: context.StackPort}, nil); err != nil {
t.Fatalf("Bind failed: %v", err)
}
c.EP.Close()
c.EP, err = c.Stack().NewEndpoint(tcp.ProtocolNumber, ipv4.ProtocolNumber, &waiter.Queue{})
if err != nil {
t.Fatalf("NewEndpoint failed; %v", err)
}
if err := c.EP.Bind(tcpip.FullAddress{Port: context.StackPort}, nil); err != nil {
t.Fatalf("Bind failed: %v", err)
}
c.EP.Close()
// Second case, an endpoint that was bound and is connecting..
c.EP, err = c.Stack().NewEndpoint(tcp.ProtocolNumber, ipv4.ProtocolNumber, &waiter.Queue{})
if err != nil {
t.Fatalf("NewEndpoint failed; %v", err)
}
if err := c.EP.Bind(tcpip.FullAddress{Port: context.StackPort}, nil); err != nil {
t.Fatalf("Bind failed: %v", err)
}
if err := c.EP.Connect(tcpip.FullAddress{Addr: context.TestAddr, Port: context.TestPort}); err != tcpip.ErrConnectStarted {
t.Fatalf("got c.EP.Connect(...) = %v, want = %v", err, tcpip.ErrConnectStarted)
}
c.EP.Close()
c.EP, err = c.Stack().NewEndpoint(tcp.ProtocolNumber, ipv4.ProtocolNumber, &waiter.Queue{})
if err != nil {
t.Fatalf("NewEndpoint failed; %v", err)
}
if err := c.EP.Bind(tcpip.FullAddress{Port: context.StackPort}, nil); err != nil {
t.Fatalf("Bind failed: %v", err)
}
c.EP.Close()
// Third case, an endpoint that was bound and is listening.
c.EP, err = c.Stack().NewEndpoint(tcp.ProtocolNumber, ipv4.ProtocolNumber, &waiter.Queue{})
if err != nil {
t.Fatalf("NewEndpoint failed; %v", err)
}
if err := c.EP.Bind(tcpip.FullAddress{Port: context.StackPort}, nil); err != nil {
t.Fatalf("Bind failed: %v", err)
}
if err := c.EP.Listen(10); err != nil {
t.Fatalf("Listen failed: %v", err)
}
c.EP.Close()
c.EP, err = c.Stack().NewEndpoint(tcp.ProtocolNumber, ipv4.ProtocolNumber, &waiter.Queue{})
if err != nil {
t.Fatalf("NewEndpoint failed; %v", err)
}
if err := c.EP.Bind(tcpip.FullAddress{Port: context.StackPort}, nil); err != nil {
t.Fatalf("Bind failed: %v", err)
}
if err := c.EP.Listen(10); err != nil {
t.Fatalf("Listen failed: %v", err)
}
}
func checkRecvBufferSize(t *testing.T, ep tcpip.Endpoint, v int) {
t.Helper()
var s tcpip.ReceiveBufferSizeOption
if err := ep.GetSockOpt(&s); err != nil {
t.Fatalf("GetSockOpt failed: %v", err)
}
if int(s) != v {
t.Fatalf("got receive buffer size = %v, want = %v", s, v)
}
}
func checkSendBufferSize(t *testing.T, ep tcpip.Endpoint, v int) {
t.Helper()
var s tcpip.SendBufferSizeOption
if err := ep.GetSockOpt(&s); err != nil {
t.Fatalf("GetSockOpt failed: %v", err)
}
if int(s) != v {
t.Fatalf("got send buffer size = %v, want = %v", s, v)
}
}
func TestDefaultBufferSizes(t *testing.T) {
s := stack.New([]string{ipv4.ProtocolName}, []string{tcp.ProtocolName}, stack.Options{})
// Check the default values.
ep, err := s.NewEndpoint(tcp.ProtocolNumber, ipv4.ProtocolNumber, &waiter.Queue{})
if err != nil {
t.Fatalf("NewEndpoint failed; %v", err)
}
defer func() {
if ep != nil {
ep.Close()
}
}()
checkSendBufferSize(t, ep, tcp.DefaultBufferSize)
checkRecvBufferSize(t, ep, tcp.DefaultBufferSize)
// Change the default send buffer size.
if err := s.SetTransportProtocolOption(tcp.ProtocolNumber, tcp.SendBufferSizeOption{1, tcp.DefaultBufferSize * 2, tcp.DefaultBufferSize * 20}); err != nil {
t.Fatalf("SetTransportProtocolOption failed: %v", err)
}
ep.Close()
ep, err = s.NewEndpoint(tcp.ProtocolNumber, ipv4.ProtocolNumber, &waiter.Queue{})
if err != nil {
t.Fatalf("NewEndpoint failed; %v", err)
}
checkSendBufferSize(t, ep, tcp.DefaultBufferSize*2)
checkRecvBufferSize(t, ep, tcp.DefaultBufferSize)
// Change the default receive buffer size.
if err := s.SetTransportProtocolOption(tcp.ProtocolNumber, tcp.ReceiveBufferSizeOption{1, tcp.DefaultBufferSize * 3, tcp.DefaultBufferSize * 30}); err != nil {
t.Fatalf("SetTransportProtocolOption failed: %v", err)
}
ep.Close()
ep, err = s.NewEndpoint(tcp.ProtocolNumber, ipv4.ProtocolNumber, &waiter.Queue{})
if err != nil {
t.Fatalf("NewEndpoint failed; %v", err)
}
checkSendBufferSize(t, ep, tcp.DefaultBufferSize*2)
checkRecvBufferSize(t, ep, tcp.DefaultBufferSize*3)
}
func TestMinMaxBufferSizes(t *testing.T) {
s := stack.New([]string{ipv4.ProtocolName}, []string{tcp.ProtocolName}, stack.Options{})
// Check the default values.
ep, err := s.NewEndpoint(tcp.ProtocolNumber, ipv4.ProtocolNumber, &waiter.Queue{})
if err != nil {
t.Fatalf("NewEndpoint failed; %v", err)
}
defer ep.Close()
// Change the min/max values for send/receive
if err := s.SetTransportProtocolOption(tcp.ProtocolNumber, tcp.ReceiveBufferSizeOption{200, tcp.DefaultBufferSize * 2, tcp.DefaultBufferSize * 20}); err != nil {
t.Fatalf("SetTransportProtocolOption failed: %v", err)
}
if err := s.SetTransportProtocolOption(tcp.ProtocolNumber, tcp.SendBufferSizeOption{300, tcp.DefaultBufferSize * 3, tcp.DefaultBufferSize * 30}); err != nil {
t.Fatalf("SetTransportProtocolOption failed: %v", err)
}
// Set values below the min.
if err := ep.SetSockOpt(tcpip.ReceiveBufferSizeOption(199)); err != nil {
t.Fatalf("GetSockOpt failed: %v", err)
}
checkRecvBufferSize(t, ep, 200)
if err := ep.SetSockOpt(tcpip.SendBufferSizeOption(299)); err != nil {
t.Fatalf("GetSockOpt failed: %v", err)
}
checkSendBufferSize(t, ep, 300)
// Set values above the max.
if err := ep.SetSockOpt(tcpip.ReceiveBufferSizeOption(1 + tcp.DefaultBufferSize*20)); err != nil {
t.Fatalf("GetSockOpt failed: %v", err)
}
checkRecvBufferSize(t, ep, tcp.DefaultBufferSize*20)
if err := ep.SetSockOpt(tcpip.SendBufferSizeOption(1 + tcp.DefaultBufferSize*30)); err != nil {
t.Fatalf("GetSockOpt failed: %v", err)
}
checkSendBufferSize(t, ep, tcp.DefaultBufferSize*30)
}
func makeStack() (*stack.Stack, *tcpip.Error) {
s := stack.New([]string{
ipv4.ProtocolName,
ipv6.ProtocolName,
}, []string{tcp.ProtocolName}, stack.Options{})
id := loopback.New()
if testing.Verbose() {
id = sniffer.New(id)
}
if err := s.CreateNIC(1, id); err != nil {
return nil, err
}
for _, ct := range []struct {
number tcpip.NetworkProtocolNumber
address tcpip.Address
}{
{ipv4.ProtocolNumber, context.StackAddr},
{ipv6.ProtocolNumber, context.StackV6Addr},
} {
if err := s.AddAddress(1, ct.number, ct.address); err != nil {
return nil, err
}
}
s.SetRouteTable([]tcpip.Route{
{
Destination: "\x00\x00\x00\x00",
Mask: "\x00\x00\x00\x00",
Gateway: "",
NIC: 1,
},
{
Destination: "\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00",
Mask: "\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00",
Gateway: "",
NIC: 1,
},
})
return s, nil
}
func TestSelfConnect(t *testing.T) {
// This test ensures that intentional self-connects work. In particular,
// it checks that if an endpoint binds to say 127.0.0.1:1000 then
// connects to 127.0.0.1:1000, then it will be connected to itself, and
// is able to send and receive data through the same endpoint.
s, err := makeStack()
if err != nil {
t.Fatal(err)
}
var wq waiter.Queue
ep, err := s.NewEndpoint(tcp.ProtocolNumber, ipv4.ProtocolNumber, &wq)
if err != nil {
t.Fatalf("NewEndpoint failed: %v", err)
}
defer ep.Close()
if err := ep.Bind(tcpip.FullAddress{Port: context.StackPort}, nil); err != nil {
t.Fatalf("Bind failed: %v", err)
}
// Register for notification, then start connection attempt.
waitEntry, notifyCh := waiter.NewChannelEntry(nil)
wq.EventRegister(&waitEntry, waiter.EventOut)
defer wq.EventUnregister(&waitEntry)
if err := ep.Connect(tcpip.FullAddress{Addr: context.StackAddr, Port: context.StackPort}); err != tcpip.ErrConnectStarted {
t.Fatalf("got ep.Connect(...) = %v, want = %v", err, tcpip.ErrConnectStarted)
}
<-notifyCh
if err := ep.GetSockOpt(tcpip.ErrorOption{}); err != nil {
t.Fatalf("Connect failed: %v", err)
}
// Write something.
data := []byte{1, 2, 3}
view := buffer.NewView(len(data))
copy(view, data)
if _, _, err := ep.Write(tcpip.SlicePayload(view), tcpip.WriteOptions{}); err != nil {
t.Fatalf("Write failed: %v", err)
}
// Read back what was written.
wq.EventUnregister(&waitEntry)
wq.EventRegister(&waitEntry, waiter.EventIn)
rd, _, err := ep.Read(nil)
if err != nil {
if err != tcpip.ErrWouldBlock {
t.Fatalf("Read failed: %v", err)
}
<-notifyCh
rd, _, err = ep.Read(nil)
if err != nil {
t.Fatalf("Read failed: %v", err)
}
}
if !bytes.Equal(data, rd) {
t.Fatalf("got data = %v, want = %v", rd, data)
}
}
func TestConnectAvoidsBoundPorts(t *testing.T) {
addressTypes := func(t *testing.T, network string) []string {
switch network {
case "ipv4":
return []string{"v4"}
case "ipv6":
return []string{"v6"}
case "dual":
return []string{"v6", "mapped"}
default:
t.Fatalf("unknown network: '%s'", network)
}
panic("unreachable")
}
address := func(t *testing.T, addressType string, isAny bool) tcpip.Address {
switch addressType {
case "v4":
if isAny {
return ""
}
return context.StackAddr
case "v6":
if isAny {
return ""
}
return context.StackV6Addr
case "mapped":
if isAny {
return context.V4MappedWildcardAddr
}
return context.StackV4MappedAddr
default:
t.Fatalf("unknown address type: '%s'", addressType)
}
panic("unreachable")
}
// This test ensures that Endpoint.Connect doesn't select already-bound ports.
networks := []string{"ipv4", "ipv6", "dual"}
for _, exhaustedNetwork := range networks {
t.Run(fmt.Sprintf("exhaustedNetwork=%s", exhaustedNetwork), func(t *testing.T) {
for _, exhaustedAddressType := range addressTypes(t, exhaustedNetwork) {
t.Run(fmt.Sprintf("exhaustedAddressType=%s", exhaustedAddressType), func(t *testing.T) {
for _, isAny := range []bool{false, true} {
t.Run(fmt.Sprintf("isAny=%t", isAny), func(t *testing.T) {
for _, candidateNetwork := range networks {
t.Run(fmt.Sprintf("candidateNetwork=%s", candidateNetwork), func(t *testing.T) {
for _, candidateAddressType := range addressTypes(t, candidateNetwork) {
t.Run(fmt.Sprintf("candidateAddressType=%s", candidateAddressType), func(t *testing.T) {
s, err := makeStack()
if err != nil {
t.Fatal(err)
}
var wq waiter.Queue
var eps []tcpip.Endpoint
defer func() {
for _, ep := range eps {
ep.Close()
}
}()
makeEP := func(network string) tcpip.Endpoint {
var networkProtocolNumber tcpip.NetworkProtocolNumber
switch network {
case "ipv4":
networkProtocolNumber = ipv4.ProtocolNumber
case "ipv6", "dual":
networkProtocolNumber = ipv6.ProtocolNumber
default:
t.Fatalf("unknown network: '%s'", network)
}
ep, err := s.NewEndpoint(tcp.ProtocolNumber, networkProtocolNumber, &wq)
if err != nil {
t.Fatalf("NewEndpoint failed: %v", err)
}
eps = append(eps, ep)
switch network {
case "ipv4":
case "ipv6":
if err := ep.SetSockOpt(tcpip.V6OnlyOption(1)); err != nil {
t.Fatalf("SetSockOpt(V6OnlyOption(1)) failed: %v", err)
}
case "dual":
if err := ep.SetSockOpt(tcpip.V6OnlyOption(0)); err != nil {
t.Fatalf("SetSockOpt(V6OnlyOption(0)) failed: %v", err)
}
default:
t.Fatalf("unknown network: '%s'", network)
}
return ep
}
var v4reserved, v6reserved bool
switch exhaustedAddressType {
case "v4", "mapped":
v4reserved = true
case "v6":
v6reserved = true
// Dual stack sockets bound to v6 any reserve on v4 as
// well.
if isAny {
switch exhaustedNetwork {
case "ipv6":
case "dual":
v4reserved = true
default:
t.Fatalf("unknown address type: '%s'", exhaustedNetwork)
}
}
default:
t.Fatalf("unknown address type: '%s'", exhaustedAddressType)
}
var collides bool
switch candidateAddressType {
case "v4", "mapped":
collides = v4reserved
case "v6":
collides = v6reserved
default:
t.Fatalf("unknown address type: '%s'", candidateAddressType)
}
for i := ports.FirstEphemeral; i <= math.MaxUint16; i++ {
if makeEP(exhaustedNetwork).Bind(tcpip.FullAddress{Addr: address(t, exhaustedAddressType, isAny), Port: uint16(i)}, nil); err != nil {
t.Fatalf("Bind(%d) failed: %v", i, err)
}
}
want := tcpip.ErrConnectStarted
if collides {
want = tcpip.ErrNoPortAvailable
}
if err := makeEP(candidateNetwork).Connect(tcpip.FullAddress{Addr: address(t, candidateAddressType, false), Port: 31337}); err != want {
t.Fatalf("got ep.Connect(..) = %v, want = %v", err, want)
}
})
}
})
}
})
}
})
}
})
}
}
func TestPathMTUDiscovery(t *testing.T) {
// This test verifies the stack retransmits packets after it receives an
// ICMP packet indicating that the path MTU has been exceeded.
c := context.New(t, 1500)
defer c.Cleanup()
// Create new connection with MSS of 1460.
const maxPayload = 1500 - header.TCPMinimumSize - header.IPv4MinimumSize
c.CreateConnectedWithRawOptions(789, 30000, nil, []byte{
header.TCPOptionMSS, 4, byte(maxPayload / 256), byte(maxPayload % 256),
})
// Send 3200 bytes of data.
const writeSize = 3200
data := buffer.NewView(writeSize)
for i := range data {
data[i] = byte(i)
}
if _, _, err := c.EP.Write(tcpip.SlicePayload(data), tcpip.WriteOptions{}); err != nil {
t.Fatalf("Write failed: %v", err)
}
receivePackets := func(c *context.Context, sizes []int, which int, seqNum uint32) []byte {
var ret []byte
for i, size := range sizes {
p := c.GetPacket()
if i == which {
ret = p
}
checker.IPv4(t, p,
checker.PayloadLen(size+header.TCPMinimumSize),
checker.TCP(
checker.DstPort(context.TestPort),
checker.SeqNum(seqNum),
checker.AckNum(790),
checker.TCPFlagsMatch(header.TCPFlagAck, ^uint8(header.TCPFlagPsh)),
),
)
seqNum += uint32(size)
}
return ret
}
// Receive three packets.
sizes := []int{maxPayload, maxPayload, writeSize - 2*maxPayload}
first := receivePackets(c, sizes, 0, uint32(c.IRS)+1)
// Send "packet too big" messages back to netstack.
const newMTU = 1200
const newMaxPayload = newMTU - header.IPv4MinimumSize - header.TCPMinimumSize
mtu := []byte{0, 0, newMTU / 256, newMTU % 256}
c.SendICMPPacket(header.ICMPv4DstUnreachable, header.ICMPv4FragmentationNeeded, mtu, first, newMTU)
// See retransmitted packets. None exceeding the new max.
sizes = []int{newMaxPayload, maxPayload - newMaxPayload, newMaxPayload, maxPayload - newMaxPayload, writeSize - 2*maxPayload}
receivePackets(c, sizes, -1, uint32(c.IRS)+1)
}
func TestTCPEndpointProbe(t *testing.T) {
c := context.New(t, 1500)
defer c.Cleanup()
invoked := make(chan struct{})
c.Stack().AddTCPProbe(func(state stack.TCPEndpointState) {
// Validate that the endpoint ID is what we expect.
//
// We don't do an extensive validation of every field but a
// basic sanity test.
if got, want := state.ID.LocalAddress, tcpip.Address(context.StackAddr); got != want {
t.Fatalf("got LocalAddress: %q, want: %q", got, want)
}
if got, want := state.ID.LocalPort, c.Port; got != want {
t.Fatalf("got LocalPort: %d, want: %d", got, want)
}
if got, want := state.ID.RemoteAddress, tcpip.Address(context.TestAddr); got != want {
t.Fatalf("got RemoteAddress: %q, want: %q", got, want)
}
if got, want := state.ID.RemotePort, uint16(context.TestPort); got != want {
t.Fatalf("got RemotePort: %d, want: %d", got, want)
}
invoked <- struct{}{}
})
c.CreateConnected(789, 30000, nil)
data := []byte{1, 2, 3}
c.SendPacket(data, &context.Headers{
SrcPort: context.TestPort,
DstPort: c.Port,
Flags: header.TCPFlagAck,
SeqNum: 790,
AckNum: c.IRS.Add(1),
RcvWnd: 30000,
})
select {
case <-invoked:
case <-time.After(100 * time.Millisecond):
t.Fatalf("TCP Probe function was not called")
}
}
func TestSetCongestionControl(t *testing.T) {
testCases := []struct {
cc tcp.CongestionControlOption
mustPass bool
}{
{"reno", true},
{"cubic", true},
}
for _, tc := range testCases {
t.Run(fmt.Sprintf("SetTransportProtocolOption(.., %v)", tc.cc), func(t *testing.T) {
c := context.New(t, 1500)
defer c.Cleanup()
s := c.Stack()
if err := s.SetTransportProtocolOption(tcp.ProtocolNumber, tc.cc); err != nil && tc.mustPass {
t.Fatalf("s.SetTransportProtocolOption(%v, %v) = %v, want not-nil", tcp.ProtocolNumber, tc.cc, err)
}
var cc tcp.CongestionControlOption
if err := s.TransportProtocolOption(tcp.ProtocolNumber, &cc); err != nil {
t.Fatalf("s.TransportProtocolOption(%v, %v) = %v", tcp.ProtocolNumber, &cc, err)
}
if got, want := cc, tc.cc; got != want {
t.Fatalf("got congestion control: %v, want: %v", got, want)
}
})
}
}
func TestAvailableCongestionControl(t *testing.T) {
c := context.New(t, 1500)
defer c.Cleanup()
s := c.Stack()
// Query permitted congestion control algorithms.
var aCC tcp.AvailableCongestionControlOption
if err := s.TransportProtocolOption(tcp.ProtocolNumber, &aCC); err != nil {
t.Fatalf("s.TransportProtocolOption(%v, %v) = %v", tcp.ProtocolNumber, &aCC, err)
}
if got, want := aCC, tcp.AvailableCongestionControlOption("reno cubic"); got != want {
t.Fatalf("got tcp.AvailableCongestionControlOption: %v, want: %v", got, want)
}
}
func TestSetAvailableCongestionControl(t *testing.T) {
c := context.New(t, 1500)
defer c.Cleanup()
s := c.Stack()
// Setting AvailableCongestionControlOption should fail.
aCC := tcp.AvailableCongestionControlOption("xyz")
if err := s.SetTransportProtocolOption(tcp.ProtocolNumber, &aCC); err == nil {
t.Fatalf("s.TransportProtocolOption(%v, %v) = nil, want non-nil", tcp.ProtocolNumber, &aCC)
}
// Verify that we still get the expected list of congestion control options.
var cc tcp.AvailableCongestionControlOption
if err := s.TransportProtocolOption(tcp.ProtocolNumber, &cc); err != nil {
t.Fatalf("s.TransportProtocolOption(%v, %v) = %v", tcp.ProtocolNumber, &cc, err)
}
if got, want := cc, tcp.AvailableCongestionControlOption("reno cubic"); got != want {
t.Fatalf("got tcp.AvailableCongestionControlOption: %v, want: %v", got, want)
}
}
func enableCUBIC(t *testing.T, c *context.Context) {
t.Helper()
opt := tcp.CongestionControlOption("cubic")
if err := c.Stack().SetTransportProtocolOption(tcp.ProtocolNumber, opt); err != nil {
t.Fatalf("c.s.SetTransportProtocolOption(tcp.ProtocolNumber, %v = %v", opt, err)
}
}
func TestKeepalive(t *testing.T) {
c := context.New(t, defaultMTU)
defer c.Cleanup()
c.CreateConnected(789, 30000, nil)
c.EP.SetSockOpt(tcpip.KeepaliveIdleOption(10 * time.Millisecond))
c.EP.SetSockOpt(tcpip.KeepaliveIntervalOption(10 * time.Millisecond))
c.EP.SetSockOpt(tcpip.KeepaliveCountOption(5))
c.EP.SetSockOpt(tcpip.KeepaliveEnabledOption(1))
// 5 unacked keepalives are sent. ACK each one, and check that the
// connection stays alive after 5.
for i := 0; i < 10; i++ {
b := c.GetPacket()
checker.IPv4(t, b,
checker.TCP(
checker.DstPort(context.TestPort),
checker.SeqNum(uint32(c.IRS)),
checker.AckNum(uint32(790)),
checker.TCPFlags(header.TCPFlagAck),
),
)
// Acknowledge the keepalive.
c.SendPacket(nil, &context.Headers{
SrcPort: context.TestPort,
DstPort: c.Port,
Flags: header.TCPFlagAck,
SeqNum: 790,
AckNum: c.IRS,
RcvWnd: 30000,
})
}
// Check that the connection is still alive.
if _, _, err := c.EP.Read(nil); err != tcpip.ErrWouldBlock {
t.Fatalf("got c.EP.Read(nil) = %v, want = %v", err, tcpip.ErrWouldBlock)
}
// Send some data and wait before ACKing it. Keepalives should be disabled
// during this period.
view := buffer.NewView(3)
if _, _, err := c.EP.Write(tcpip.SlicePayload(view), tcpip.WriteOptions{}); err != nil {
t.Fatalf("Write failed: %v", err)
}
next := uint32(c.IRS) + 1
checker.IPv4(t, c.GetPacket(),
checker.PayloadLen(len(view)+header.TCPMinimumSize),
checker.TCP(
checker.DstPort(context.TestPort),
checker.SeqNum(next),
checker.AckNum(790),
checker.TCPFlagsMatch(header.TCPFlagAck, ^uint8(header.TCPFlagPsh)),
),
)
// Wait for the packet to be retransmitted. Verify that no keepalives
// were sent.
checker.IPv4(t, c.GetPacket(),
checker.PayloadLen(len(view)+header.TCPMinimumSize),
checker.TCP(
checker.DstPort(context.TestPort),
checker.SeqNum(next),
checker.AckNum(790),
checker.TCPFlags(header.TCPFlagAck|header.TCPFlagPsh),
),
)
c.CheckNoPacket("Keepalive packet received while unACKed data is pending")
next += uint32(len(view))
// Send ACK. Keepalives should start sending again.
c.SendPacket(nil, &context.Headers{
SrcPort: context.TestPort,
DstPort: c.Port,
Flags: header.TCPFlagAck,
SeqNum: 790,
AckNum: seqnum.Value(next),
RcvWnd: 30000,
})
// Now receive 5 keepalives, but don't ACK them. The connection
// should be reset after 5.
for i := 0; i < 5; i++ {
b := c.GetPacket()
checker.IPv4(t, b,
checker.TCP(
checker.DstPort(context.TestPort),
checker.SeqNum(uint32(next-1)),
checker.AckNum(uint32(790)),
checker.TCPFlags(header.TCPFlagAck),
),
)
}
// The connection should be terminated after 5 unacked keepalives.
checker.IPv4(t, c.GetPacket(),
checker.TCP(
checker.DstPort(context.TestPort),
checker.SeqNum(uint32(next)),
checker.AckNum(uint32(790)),
checker.TCPFlags(header.TCPFlagAck|header.TCPFlagRst),
),
)
if _, _, err := c.EP.Read(nil); err != tcpip.ErrConnectionReset {
t.Fatalf("got c.EP.Read(nil) = %v, want = %v", err, tcpip.ErrConnectionReset)
}
}