diff options
| -rw-r--r-- | test/packetimpact/testbench/connections.go | 14 | ||||
| -rw-r--r-- | test/packetimpact/tests/BUILD | 13 | ||||
| -rw-r--r-- | test/packetimpact/tests/tcp_close_wait_ack_test.go | 102 |
3 files changed, 126 insertions, 3 deletions
diff --git a/test/packetimpact/testbench/connections.go b/test/packetimpact/testbench/connections.go index be62d051d..c1b3c4380 100644 --- a/test/packetimpact/testbench/connections.go +++ b/test/packetimpact/testbench/connections.go @@ -189,6 +189,7 @@ type tcpState struct { localSeqNum, remoteSeqNum *seqnum.Value synAck *TCP portPickerFD int + finSent bool } var _ layerState = (*tcpState)(nil) @@ -210,6 +211,7 @@ func newTCPState(out, in TCP) (*tcpState, error) { in: TCP{DstPort: &localPort}, localSeqNum: SeqNumValue(seqnum.Value(rand.Uint32())), portPickerFD: portPickerFD, + finSent: false, } if err := s.out.merge(&out); err != nil { return nil, err @@ -254,12 +256,18 @@ func (s *tcpState) sent(sent Layer) error { if !ok { return fmt.Errorf("can't update tcpState with %T Layer", sent) } - for current := tcp.next(); current != nil; current = current.next() { - s.localSeqNum.UpdateForward(seqnum.Size(current.length())) + if !s.finSent { + // update localSeqNum by the payload only when FIN is not yet sent by us + for current := tcp.next(); current != nil; current = current.next() { + s.localSeqNum.UpdateForward(seqnum.Size(current.length())) + } } if tcp.Flags != nil && *tcp.Flags&(header.TCPFlagSyn|header.TCPFlagFin) != 0 { s.localSeqNum.UpdateForward(1) } + if *tcp.Flags&(header.TCPFlagFin) != 0 { + s.finSent = true + } return nil } @@ -590,7 +598,7 @@ func (conn *TCPIPv4) RemoteSeqNum() *seqnum.Value { return conn.state().remoteSeqNum } -// LocalSeqNum returns the next expected sequence number from the DUT. +// LocalSeqNum returns the next sequence number to send from the testbench. func (conn *TCPIPv4) LocalSeqNum() *seqnum.Value { return conn.state().localSeqNum } diff --git a/test/packetimpact/tests/BUILD b/test/packetimpact/tests/BUILD index 4f8c8bdc0..690cee140 100644 --- a/test/packetimpact/tests/BUILD +++ b/test/packetimpact/tests/BUILD @@ -75,6 +75,19 @@ packetimpact_go_test( ], ) +packetimpact_go_test( + name = "tcp_close_wait_ack", + srcs = ["tcp_close_wait_ack_test.go"], + # TODO(b/153574037): Fix netstack then remove the line below. + netstack = False, + deps = [ + "//pkg/tcpip/header", + "//pkg/tcpip/seqnum", + "//test/packetimpact/testbench", + "@org_golang_x_sys//unix:go_default_library", + ], +) + sh_binary( name = "test_runner", srcs = ["test_runner.sh"], diff --git a/test/packetimpact/tests/tcp_close_wait_ack_test.go b/test/packetimpact/tests/tcp_close_wait_ack_test.go new file mode 100644 index 000000000..eb4cc7a65 --- /dev/null +++ b/test/packetimpact/tests/tcp_close_wait_ack_test.go @@ -0,0 +1,102 @@ +// Copyright 2020 The gVisor Authors. +// +// 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_close_wait_ack_test + +import ( + "fmt" + "testing" + "time" + + "golang.org/x/sys/unix" + "gvisor.dev/gvisor/pkg/tcpip/header" + "gvisor.dev/gvisor/pkg/tcpip/seqnum" + tb "gvisor.dev/gvisor/test/packetimpact/testbench" +) + +func TestCloseWaitAck(t *testing.T) { + for _, tt := range []struct { + description string + makeTestingTCP func(conn *tb.TCPIPv4, seqNumOffset seqnum.Size) tb.TCP + seqNumOffset seqnum.Size + expectAck bool + }{ + {"OTW", GenerateOTWSeqSegment, 0, false}, + {"OTW", GenerateOTWSeqSegment, 1, true}, + {"OTW", GenerateOTWSeqSegment, 2, true}, + {"ACK", GenerateUnaccACKSegment, 0, false}, + {"ACK", GenerateUnaccACKSegment, 1, true}, + {"ACK", GenerateUnaccACKSegment, 2, true}, + } { + t.Run(fmt.Sprintf("%s%d", tt.description, tt.seqNumOffset), func(t *testing.T) { + dut := tb.NewDUT(t) + defer dut.TearDown() + listenFd, remotePort := dut.CreateListener(unix.SOCK_STREAM, unix.IPPROTO_TCP, 1) + defer dut.Close(listenFd) + conn := tb.NewTCPIPv4(t, tb.TCP{DstPort: &remotePort}, tb.TCP{SrcPort: &remotePort}) + defer conn.Close() + + conn.Handshake() + acceptFd, _ := dut.Accept(listenFd) + + // Send a FIN to DUT to intiate the active close + conn.Send(tb.TCP{Flags: tb.Uint8(header.TCPFlagAck | header.TCPFlagFin)}) + if _, err := conn.Expect(tb.TCP{Flags: tb.Uint8(header.TCPFlagAck)}, time.Second); err != nil { + t.Fatalf("expected an ACK for our fin and DUT should enter CLOSE_WAIT: %s", err) + } + + // Send a segment with OTW Seq / unacc ACK and expect an ACK back + conn.Send(tt.makeTestingTCP(&conn, tt.seqNumOffset), &tb.Payload{Bytes: []byte("Sample Data")}) + gotAck, err := conn.Expect(tb.TCP{Flags: tb.Uint8(header.TCPFlagAck)}, time.Second) + if tt.expectAck && err != nil { + t.Fatalf("expected an ack but got none: %s", err) + } + if !tt.expectAck && gotAck != nil { + t.Fatalf("expected no ack but got one: %s", gotAck) + } + + // Now let's verify DUT is indeed in CLOSE_WAIT + dut.Close(acceptFd) + if _, err := conn.Expect(tb.TCP{Flags: tb.Uint8(header.TCPFlagAck | header.TCPFlagFin)}, time.Second); err != nil { + t.Fatalf("expected DUT to send a FIN: %s", err) + } + // Ack the FIN from DUT + conn.Send(tb.TCP{Flags: tb.Uint8(header.TCPFlagAck)}) + // Send some extra data to DUT + conn.Send(tb.TCP{Flags: tb.Uint8(header.TCPFlagAck)}, &tb.Payload{Bytes: []byte("Sample Data")}) + if _, err := conn.Expect(tb.TCP{Flags: tb.Uint8(header.TCPFlagRst)}, time.Second); err != nil { + t.Fatalf("expected DUT to send an RST: %s", err) + } + }) + } +} + +// This generates an segment with seqnum = RCV.NXT + RCV.WND + seqNumOffset, the +// generated segment is only acceptable when seqNumOffset is 0, otherwise an ACK +// is expected from the receiver. +func GenerateOTWSeqSegment(conn *tb.TCPIPv4, seqNumOffset seqnum.Size) tb.TCP { + windowSize := seqnum.Size(*conn.SynAck().WindowSize) + lastAcceptable := conn.LocalSeqNum().Add(windowSize - 1) + otwSeq := uint32(lastAcceptable.Add(seqNumOffset)) + return tb.TCP{SeqNum: tb.Uint32(otwSeq), Flags: tb.Uint8(header.TCPFlagAck)} +} + +// This generates an segment with acknum = SND.NXT + seqNumOffset, the generated +// segment is only acceptable when seqNumOffset is 0, otherwise an ACK is +// expected from the receiver. +func GenerateUnaccACKSegment(conn *tb.TCPIPv4, seqNumOffset seqnum.Size) tb.TCP { + lastAcceptable := conn.RemoteSeqNum() + unaccAck := uint32(lastAcceptable.Add(seqNumOffset)) + return tb.TCP{AckNum: tb.Uint32(unaccAck), Flags: tb.Uint8(header.TCPFlagAck)} +} |