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seqs_test.go
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package seqs_test
import (
"strconv"
"testing"
"github.com/soypat/seqs"
"github.com/soypat/seqs/eth"
)
const (
SYNACK = seqs.FlagSYN | seqs.FlagACK
FINACK = seqs.FlagFIN | seqs.FlagACK
PSHACK = seqs.FlagPSH | seqs.FlagACK
)
/*
Section 3.5 of RFC 9293: Basic 3-way handshake for connection synchronization.
TCP Peer A TCP Peer B
1. CLOSED LISTEN
2. SYN-SENT --> <SEQ=100><CTL=SYN> --> SYN-RECEIVED
3. ESTABLISHED <-- <SEQ=300><ACK=101><CTL=SYN,ACK> <-- SYN-RECEIVED
4. ESTABLISHED --> <SEQ=101><ACK=301><CTL=ACK> --> ESTABLISHED
5. ESTABLISHED --> <SEQ=101><ACK=301><CTL=ACK><DATA> --> ESTABLISHED
*/
func TestExchange_rfc9293_figure6(t *testing.T) {
const issA, issB, windowA, windowB = 100, 300, 1000, 1000
exchangeA := []seqs.Exchange{
{ // A sends SYN to B.
Outgoing: &seqs.Segment{SEQ: issA, Flags: seqs.FlagSYN, WND: windowA},
WantState: seqs.StateSynSent,
WantPeerState: seqs.StateSynRcvd,
},
{ // A receives SYNACK from B thus establishing the connection on A's side.
Incoming: &seqs.Segment{SEQ: issB, ACK: issA + 1, Flags: SYNACK, WND: windowB},
WantState: seqs.StateEstablished,
WantPending: &seqs.Segment{SEQ: issA + 1, ACK: issB + 1, Flags: seqs.FlagACK, WND: windowA},
WantPeerState: seqs.StateSynRcvd,
},
{ // A sends ACK to B, which leaves connection established on their side. Three way handshake complete by now.
Outgoing: &seqs.Segment{SEQ: issA + 1, ACK: issB + 1, Flags: seqs.FlagACK, WND: windowA},
WantState: seqs.StateEstablished,
WantPeerState: seqs.StateEstablished,
},
}
var tcbA seqs.ControlBlock
tcbA.HelperInitState(seqs.StateSynSent, issA, issA, windowA)
tcbA.HelperExchange(t, exchangeA)
segA, ok := tcbA.PendingSegment(0)
if ok {
t.Error("unexpected Client pending segment after establishment: ", segA)
}
exchangeB := reverseExchange(exchangeA)
var tcbB seqs.ControlBlock
tcbB.HelperInitState(seqs.StateListen, issB, issB, windowB)
tcbB.HelperExchange(t, exchangeB) // TODO remove [:3] after snd.UNA bugfix
segB, ok := tcbB.PendingSegment(0)
if ok {
t.Error("unexpected Listener pending segment after establishment: ", segB)
}
}
/*
Section 3.5 of RFC 9293: Simultaneous Connection Synchronization (SYN).
TCP Peer A TCP Peer B
1. CLOSED CLOSED
2. SYN-SENT --> <SEQ=100><CTL=SYN> ...
3. SYN-RECEIVED <-- <SEQ=300><CTL=SYN> <-- SYN-SENT
4. ... <SEQ=100><CTL=SYN> --> SYN-RECEIVED
5. SYN-RECEIVED --> <SEQ=100><ACK=301><CTL=SYN,ACK> ...
6. ESTABLISHED <-- <SEQ=300><ACK=101><CTL=SYN,ACK> <-- SYN-RECEIVED
7. ... <SEQ=100><ACK=301><CTL=SYN,ACK> --> ESTABLISHED
*/
func TestExchange_rfc9293_figure7(t *testing.T) {
const issA, issB, windowA, windowB = 100, 300, 1000, 1000
exchangeA := []seqs.Exchange{
0: { // A sends SYN to B.
Outgoing: &seqs.Segment{SEQ: issA, Flags: seqs.FlagSYN, WND: windowA},
WantState: seqs.StateSynSent,
},
1: { // A receives a SYN with no ACK from B.
Incoming: &seqs.Segment{SEQ: issB, Flags: seqs.FlagSYN, WND: windowB},
WantState: seqs.StateSynRcvd,
WantPending: &seqs.Segment{SEQ: issA, ACK: issB + 1, Flags: SYNACK, WND: windowA},
},
2: { // A sends SYNACK to B.
Outgoing: &seqs.Segment{SEQ: issA, ACK: issB + 1, Flags: SYNACK, WND: windowA},
WantState: seqs.StateSynRcvd,
},
3: { // A receives ACK from B.
Incoming: &seqs.Segment{SEQ: issB, ACK: issA + 1, Flags: SYNACK, WND: windowA},
WantState: seqs.StateEstablished,
},
}
var tcbA seqs.ControlBlock
tcbA.HelperInitState(seqs.StateSynSent, issA, issA, windowA)
tcbA.HelperExchange(t, exchangeA)
}
/*
Recovery from Old Duplicate SYN
TCP Peer A TCP Peer B
1. CLOSED LISTEN
2. SYN-SENT --> <SEQ=100><CTL=SYN> ...
3. (duplicate) ... <SEQ=90><CTL=SYN> --> SYN-RECEIVED
4. SYN-SENT <-- <SEQ=300><ACK=91><CTL=SYN,ACK> <-- SYN-RECEIVED
5. SYN-SENT --> <SEQ=91><CTL=RST> --> LISTEN
6. ... <SEQ=100><CTL=SYN> --> SYN-RECEIVED
7. ESTABLISHED <-- <SEQ=400><ACK=101><CTL=SYN,ACK> <-- SYN-RECEIVED
8. ESTABLISHED --> <SEQ=101><ACK=401><CTL=ACK> --> ESTABLISHED
*/
func TestExchange_rfc9293_figure8(t *testing.T) {
const issA, issB, windowA, windowB = 100, 300, 1000, 1000
const issAold = 90
const issBNew = issB + seqs.RSTJump
exchangeA := []seqs.Exchange{
0: { // A sends new SYN to B (which is not received).
Outgoing: &seqs.Segment{SEQ: issA, Flags: seqs.FlagSYN, WND: windowA},
WantState: seqs.StateSynSent,
WantPeerState: seqs.StateSynRcvd,
},
1: { // Receive SYN from B acking an old "duplicate" SYN.
Incoming: &seqs.Segment{SEQ: issB, ACK: issAold + 1, Flags: SYNACK, WND: windowB},
WantState: seqs.StateSynSent,
WantPending: &seqs.Segment{SEQ: issAold + 1, Flags: seqs.FlagRST, WND: windowA},
WantPeerState: seqs.StateSynRcvd,
},
2: { // A sends RST to B and makes segment believable by using the old SEQ.
Outgoing: &seqs.Segment{SEQ: issAold + 1, Flags: seqs.FlagRST, WND: windowA},
WantState: seqs.StateSynSent,
WantPeerState: seqs.StateListen,
},
3: { // A sends a duplicate SYN to B.
Outgoing: &seqs.Segment{SEQ: issA, Flags: seqs.FlagSYN, WND: windowA},
WantState: seqs.StateSynSent,
WantPeerState: seqs.StateSynRcvd,
},
4: { // B SYNACKs new SYN.
Incoming: &seqs.Segment{SEQ: issBNew, ACK: issA + 1, Flags: SYNACK, WND: windowB},
WantState: seqs.StateEstablished,
WantPending: &seqs.Segment{SEQ: issA + 1, ACK: issBNew + 1, Flags: seqs.FlagACK, WND: windowA},
WantPeerState: seqs.StateSynRcvd,
},
5: { // B receives ACK from A.
Outgoing: &seqs.Segment{SEQ: issA + 1, ACK: issBNew + 1, Flags: seqs.FlagACK, WND: windowA},
WantState: seqs.StateEstablished,
WantPeerState: seqs.StateEstablished,
},
}
var tcbA seqs.ControlBlock
tcbA.HelperInitState(seqs.StateSynSent, issA, issA, windowA)
tcbA.HelperExchange(t, exchangeA)
exchangeB := []seqs.Exchange{
0: { // B receives old SYN from A.
Incoming: &seqs.Segment{SEQ: issAold, Flags: seqs.FlagSYN, WND: windowA},
WantState: seqs.StateSynRcvd,
WantPending: &seqs.Segment{SEQ: issB, ACK: issAold + 1, Flags: SYNACK, WND: windowB},
},
1: { // B SYNACKs old SYN.
Outgoing: &seqs.Segment{SEQ: issB, ACK: issAold + 1, Flags: SYNACK, WND: windowB},
WantState: seqs.StateSynRcvd,
},
2: { // B receives RST from A.
Incoming: &seqs.Segment{SEQ: issAold + 1, Flags: seqs.FlagRST, WND: windowA},
WantState: seqs.StateListen,
},
3: { // B receives new SYN from A.
Incoming: &seqs.Segment{SEQ: issA, Flags: seqs.FlagSYN, WND: windowA},
WantState: seqs.StateSynRcvd,
WantPending: &seqs.Segment{SEQ: issBNew, ACK: issA + 1, Flags: SYNACK, WND: windowB},
},
4: { // B SYNACKs new SYN.
Outgoing: &seqs.Segment{SEQ: issBNew, ACK: issA + 1, Flags: SYNACK, WND: windowB},
WantState: seqs.StateSynRcvd,
},
5: { // B receives ACK from A.
Incoming: &seqs.Segment{SEQ: issA + 1, ACK: issBNew + 1, Flags: seqs.FlagACK, WND: windowA},
WantState: seqs.StateEstablished,
},
}
var tcbB seqs.ControlBlock
tcbB.HelperInitState(seqs.StateListen, issB, issB, windowB)
tcbB.HelperExchange(t, exchangeB)
}
/*
Figure 12: Normal Close Sequence
TCP Peer A TCP Peer B
1. ESTABLISHED ESTABLISHED
2. (Close)
FIN-WAIT-1 --> <SEQ=100><ACK=300><CTL=FIN,ACK> --> CLOSE-WAIT
3. FIN-WAIT-2 <-- <SEQ=300><ACK=101><CTL=ACK> <-- CLOSE-WAIT
4. (Close)
TIME-WAIT <-- <SEQ=300><ACK=101><CTL=FIN,ACK> <-- LAST-ACK
5. TIME-WAIT --> <SEQ=101><ACK=301><CTL=ACK> --> CLOSED
6. (2 MSL)
CLOSED
*/
func TestExchange_rfc9293_figure12(t *testing.T) {
const issA, issB, windowA, windowB = 100, 300, 1000, 1000
exchangeA := []seqs.Exchange{
0: { // A sends FIN|ACK to B to begin closing connection.
Outgoing: &seqs.Segment{SEQ: issA, ACK: issB, Flags: FINACK, WND: windowA},
WantState: seqs.StateFinWait1,
WantPeerState: seqs.StateCloseWait,
},
1: { // A receives ACK from B.
Incoming: &seqs.Segment{SEQ: issB, ACK: issA + 1, Flags: seqs.FlagACK, WND: windowB},
WantState: seqs.StateFinWait2,
WantPeerState: seqs.StateCloseWait,
// TODO(soypat): WantPending should be nil here? Perhaps fix test by modifying rcvFinWait1 pending result.
WantPending: &seqs.Segment{SEQ: issA + 1, ACK: issB, Flags: seqs.FlagACK, WND: windowA},
},
2: { // A receives FIN|ACK from B.
Incoming: &seqs.Segment{SEQ: issB, ACK: issA + 1, Flags: FINACK, WND: windowB},
WantState: seqs.StateTimeWait,
WantPending: &seqs.Segment{SEQ: issA + 1, ACK: issB + 1, Flags: seqs.FlagACK, WND: windowA},
WantPeerState: seqs.StateLastAck,
},
3: { // A sends ACK to B.
Outgoing: &seqs.Segment{SEQ: issA + 1, ACK: issB + 1, Flags: seqs.FlagACK, WND: windowA},
WantState: seqs.StateTimeWait, // Technically we should be in TimeWait here.
WantPeerState: seqs.StateClosed,
},
}
var tcbA seqs.ControlBlock
tcbA.HelperInitState(seqs.StateEstablished, issA, issA, windowA)
tcbA.HelperInitRcv(issB, issB, windowB)
tcbA.HelperExchange(t, exchangeA)
// tcbA.HelperExchange(t, exchangeA[:1])
// tcbA.HelperExchange(t, exchangeA[1:2])
// tcbA.HelperExchange(t, exchangeA[2:])
return
exchangeB := reverseExchange(exchangeA)
exchangeB[1].WantPending = &seqs.Segment{SEQ: issB, ACK: issA + 1, Flags: FINACK, WND: windowB}
var tcbB seqs.ControlBlock
tcbB.HelperInitState(seqs.StateEstablished, issB, issB, windowB)
tcbB.HelperInitRcv(issA, issA, windowA)
tcbB.HelperExchange(t, exchangeB)
}
/*
Figure 12: Simultaneous Close Sequence
TCP Peer A TCP Peer B
1. ESTABLISHED ESTABLISHED
2. (Close) (Close)
FIN-WAIT-1 --> <SEQ=100><ACK=300><CTL=FIN,ACK> ... FIN-WAIT-1
<-- <SEQ=300><ACK=100><CTL=FIN,ACK> <--
... <SEQ=100><ACK=300><CTL=FIN,ACK> -->
3. CLOSING --> <SEQ=101><ACK=301><CTL=ACK> ... CLOSING
<-- <SEQ=301><ACK=101><CTL=ACK> <--
... <SEQ=101><ACK=301><CTL=ACK> -->
4. TIME-WAIT TIME-WAIT
(2 MSL) (2 MSL)
CLOSED CLOSED
*/
func TestExchange_rfc9293_figure13(t *testing.T) {
const issA, issB, windowA, windowB = 100, 300, 1000, 1000
exchangeA := []seqs.Exchange{
0: { // A sends FIN|ACK to B to begin closing connection.
Outgoing: &seqs.Segment{SEQ: issA, ACK: issB, Flags: FINACK, WND: windowA},
WantState: seqs.StateFinWait1,
},
1: { // A receives FIN|ACK from B, who sent packet before receiving A's FINACK.
Incoming: &seqs.Segment{SEQ: issB, ACK: issA, Flags: FINACK, WND: windowB},
WantState: seqs.StateClosing,
WantPending: &seqs.Segment{SEQ: issA + 1, ACK: issB + 1, Flags: seqs.FlagACK, WND: windowA},
},
2: { // A sends ACK to B.
Outgoing: &seqs.Segment{SEQ: issA + 1, ACK: issB + 1, Flags: seqs.FlagACK, WND: windowA},
WantState: seqs.StateTimeWait,
},
}
var tcbA seqs.ControlBlock
tcbA.HelperInitState(seqs.StateEstablished, issA, issA, windowA)
tcbA.HelperInitRcv(issB, issB, windowB)
tcbA.HelperExchange(t, exchangeA)
// No need to test B since exchange is completely symmetric.
}
// Check no duplicate ack is sent during establishment.
func TestExchange_noDupAckDuringEstablished(t *testing.T) {
var tcbA seqs.ControlBlock
const issA, issB, windowA, windowB = 300, 334222749, 256, 64240
err := tcbA.Open(issA, issA, seqs.StateSynSent)
tcbA.SetRecvWindow(windowA)
if err != nil {
t.Fatal(err)
}
establishA := []seqs.Exchange{
0: { // B sends SYN to A.
Incoming: &seqs.Segment{SEQ: issB, ACK: 0, WND: windowB, Flags: seqs.FlagSYN},
WantPending: &seqs.Segment{SEQ: issA, ACK: issB + 1, WND: windowA, Flags: SYNACK},
WantState: seqs.StateSynRcvd,
},
1: { // Send SYNACK to B.
Outgoing: &seqs.Segment{SEQ: issA, ACK: issB + 1, WND: windowA, Flags: SYNACK},
WantState: seqs.StateSynRcvd,
},
2: { // B ACKs SYNACK, thus establishing the connection on both sides.
Incoming: &seqs.Segment{SEQ: issB + 1, ACK: issA + 1, WND: windowB, Flags: seqs.FlagACK},
WantState: seqs.StateEstablished,
},
}
tcbA.HelperExchange(t, establishA)
if tcbA.State() != seqs.StateEstablished {
t.Fatal("expected established state")
}
checkNoPending(t, &tcbA)
const datasize = 5
dataExA := []seqs.Exchange{
0: { // B sends PSH|ACK to A with data.
Incoming: &seqs.Segment{SEQ: issB + 1, ACK: issA + 1, WND: windowB, Flags: PSHACK, DATALEN: datasize},
WantPending: &seqs.Segment{SEQ: issA + 1, ACK: issB + 1 + datasize, WND: windowA, Flags: seqs.FlagACK},
WantState: seqs.StateEstablished,
},
1: { // A ACKs B's data.
Outgoing: &seqs.Segment{SEQ: issA + 1, ACK: issB + 1 + datasize, WND: windowA, Flags: seqs.FlagACK},
WantState: seqs.StateEstablished,
},
2: { // A sends PSH|ACK to B with data, same amount, as if echoing.
Outgoing: &seqs.Segment{SEQ: issA + 1, ACK: issB + 1 + datasize, WND: windowA, Flags: PSHACK, DATALEN: datasize},
WantState: seqs.StateEstablished,
},
// 3: { // B ACKs A's data.
// Incoming: &seqs.Segment{SEQ: issB + 1 + datasize, ACK: issA + 1 + datasize, WND: windowB, Flags: seqs.FlagACK},
// WantPending: nil,
// WantState: seqs.StateEstablished,
// },
}
tcbA.HelperExchange(t, dataExA)
checkNoPending(t, &tcbA)
tcbA.Recv(seqs.Segment{SEQ: issB + 1 + datasize, ACK: issA + 1 + datasize, WND: windowB, Flags: seqs.FlagACK})
checkNoPending(t, &tcbA)
}
// This test reenacts a full client-server interaction in the sending and receiving
// of the 12 byte message "hello world\n" over TCP.
func TestExchange_helloworld(t *testing.T) {
// Client Transmission Control Block.
var tcbA seqs.ControlBlock
const windowA, windowB = 502, 4096
const issA, issB = 0x5e722b7d, 0xbe6e4c0f
const datalen = 12
exchangeA := []seqs.Exchange{
0: { // A sends SYN to B.
Outgoing: &seqs.Segment{SEQ: issA, Flags: seqs.FlagSYN, WND: windowA},
WantState: seqs.StateSynSent,
WantPeerState: seqs.StateSynRcvd,
},
1: { // A receives SYNACK from B.
Incoming: &seqs.Segment{SEQ: issB, ACK: issA + 1, Flags: SYNACK, WND: windowB},
WantState: seqs.StateEstablished,
WantPending: &seqs.Segment{SEQ: issA + 1, ACK: issB + 1, Flags: seqs.FlagACK, WND: windowA},
WantPeerState: seqs.StateSynRcvd,
},
2: { // A sends ACK to B thus establishing connection.
Outgoing: &seqs.Segment{SEQ: issA + 1, ACK: issB + 1, Flags: seqs.FlagACK, WND: windowA},
WantState: seqs.StateEstablished,
WantPeerState: seqs.StateEstablished,
},
3: { // A sends PSH|ACK to B with 12 byte message: "hello world\n"
Outgoing: &seqs.Segment{SEQ: issA + 1, ACK: issB + 1, Flags: PSHACK, WND: windowA, DATALEN: datalen},
WantState: seqs.StateEstablished,
WantPeerState: seqs.StateEstablished,
},
4: { // A receives ACK from B of last message.
Incoming: &seqs.Segment{SEQ: issB + 1, ACK: issA + 1 + datalen, Flags: seqs.FlagACK, WND: windowB},
WantState: seqs.StateEstablished,
WantPeerState: seqs.StateEstablished,
},
5: { // A receives PSH|ACK from B with echoed 12 byte message: "hello world\n"
Incoming: &seqs.Segment{SEQ: issB + 1, ACK: issA + 1 + datalen, Flags: PSHACK, WND: windowB, DATALEN: datalen},
WantState: seqs.StateEstablished,
WantPending: &seqs.Segment{SEQ: issA + 1 + datalen, ACK: issB + 1 + datalen, Flags: seqs.FlagACK, WND: windowA},
WantPeerState: seqs.StateEstablished,
},
6: { // A ACKs B's message.
Outgoing: &seqs.Segment{SEQ: issA + 1 + datalen, ACK: issB + 1 + datalen, Flags: seqs.FlagACK, WND: windowA},
WantState: seqs.StateEstablished,
WantPeerState: seqs.StateEstablished,
},
7: { // A sends PSH|ACK to B with SECOND 12 byte message.
Outgoing: &seqs.Segment{SEQ: issA + 1 + datalen, ACK: issB + 1 + datalen, Flags: PSHACK, WND: windowA, DATALEN: datalen},
WantState: seqs.StateEstablished,
WantPeerState: seqs.StateEstablished,
},
8: { // A receives PSH|ACK that acks last message and contains echoed of SECOND 12 byte message.
Incoming: &seqs.Segment{SEQ: issB + 1 + datalen, ACK: issA + 1 + 2*datalen, Flags: PSHACK, WND: windowB, DATALEN: datalen},
WantState: seqs.StateEstablished,
WantPending: &seqs.Segment{SEQ: issA + 1 + 2*datalen, ACK: issB + 1 + 2*datalen, Flags: seqs.FlagACK, WND: windowA},
WantPeerState: seqs.StateEstablished,
},
9: { // A ACKs B's SECOND message.
Outgoing: &seqs.Segment{SEQ: issA + 1 + 2*datalen, ACK: issB + 1 + 2*datalen, Flags: seqs.FlagACK, WND: windowA},
WantState: seqs.StateEstablished,
WantPeerState: seqs.StateEstablished,
},
10: { // A sends FIN|ACK to B to close connection.
Outgoing: &seqs.Segment{SEQ: issA + 1 + 2*datalen, ACK: issB + 1 + 2*datalen, Flags: FINACK, WND: windowA},
WantState: seqs.StateFinWait1,
WantPeerState: seqs.StateCloseWait,
},
11: { // A receives B's ACK of FIN.
Incoming: &seqs.Segment{SEQ: issB + 1 + 2*datalen, ACK: issA + 2 + 2*datalen, Flags: seqs.FlagACK, WND: windowB},
WantState: seqs.StateFinWait2,
WantPending: &seqs.Segment{SEQ: issA + 2 + 2*datalen, ACK: issB + 1 + 2*datalen, Flags: seqs.FlagACK, WND: windowA},
WantPeerState: seqs.StateCloseWait,
},
}
// The client starts in the SYN_SENT state with a random sequence number.
gotServerSeg, _ := parseSegment(t, exchangeHelloWorld[0])
tcbA.HelperInitState(seqs.StateSynSent, gotServerSeg.SEQ, gotServerSeg.SEQ, windowB)
tcbA.HelperExchange(t, exchangeA)
// TODO(soypat): fix exchange reversal.
return
exchangeB := reverseExchange(exchangeA)
exchangeB[7].WantPending = nil // Is an unpredicable action.
var tcbB seqs.ControlBlock
tcbB.HelperInitState(seqs.StateListen, issB, issB, windowB)
tcbB.HelperInitRcv(issA, issA, windowA)
tcbB.HelperExchange(t, exchangeB)
}
func TestResetEstablished(t *testing.T) {
var tcb seqs.ControlBlock
const windowA, windowB = 502, 4096
const issA, issB = 0x5e722b7d, 0xbe6e4c0f
tcb.HelperInitState(seqs.StateEstablished, issA, issA, windowA)
tcb.HelperInitRcv(issB, issB, windowB)
err := tcb.Recv(seqs.Segment{SEQ: issB, ACK: issA, Flags: seqs.FlagRST, WND: windowB})
if err == nil {
t.Fatal("expected error")
}
if tcb.State() != seqs.StateClosed {
t.Error("expected closed state; got ", tcb.State().String())
}
checkNoPending(t, &tcb)
}
func TestExchange_helloworld_client(t *testing.T) {
return
// Client Transmission Control Block.
var tcb seqs.ControlBlock
// The client starts in the SYN_SENT state with a random sequence number.
gotClientSeg, _ := parseSegment(t, exchangeHelloWorld[0])
// We add the SYN state to the client.
tcb.HelperInitState(seqs.StateSynSent, gotClientSeg.SEQ, gotClientSeg.SEQ, gotClientSeg.WND)
err := tcb.Send(gotClientSeg)
if err != nil {
t.Fatal(err)
}
tcb.HelperPrintSegment(t, false, gotClientSeg)
segString := func(seg seqs.Segment) string {
return tcb.RelativeAutoSegment(seg).RelativeGoString(0, 0)
}
for i, packet := range exchangeHelloWorld {
if i == 0 {
continue // we already processed first packet.
}
seg, payload := parseSegment(t, packet)
if seg.DATALEN > 0 {
t.Logf("seg[%d] <%s> payload: %q", i, tcb.State(), string(payload))
} else {
t.Logf("seg[%d] <%s>", i, tcb.State())
}
isClient := packet[0] == 0x28
if isClient {
isPSH := seg.Flags&seqs.FlagPSH != 0
gotClientSeg.Flags |= seg.Flags & (seqs.FlagPSH | seqs.FlagFIN) // Can't predict when client will send FIN.
if isPSH {
gotClientSeg.DATALEN = seg.DATALEN
}
gotClientSeg.WND = seg.WND // Ignore window field, not a core part of control flow.
if gotClientSeg != seg {
t.Fatalf("client:\n got=%+v\nwant=%+v", segString(gotClientSeg), segString(seg))
}
err := tcb.Send(gotClientSeg)
if err != nil {
t.Fatalf("incoming %s:\nseg[%d]=%s\nrcv=%+v\nsnd=%+v", err, i, segString(gotClientSeg), tcb.RelativeRecvSpace(), tcb.RelativeSendSpace())
}
tcb.HelperPrintSegment(t, false, gotClientSeg)
continue // we only pass server packets to the client.
}
err = tcb.Recv(seg)
if err != nil {
t.Fatalf("%s:\nseg[%d]=%s\nrcv=%+v\nsnd=%+v", err, i, segString(seg), tcb.RelativeRecvSpace(), tcb.RelativeSendSpace())
}
tcb.HelperPrintSegment(t, true, seg)
var ok bool
gotClientSeg, ok = tcb.PendingSegment(0)
if !ok {
t.Fatalf("[%d]: got no segment state=%s", i, tcb.State())
}
}
}
func parseSegment(t *testing.T, b []byte) (seqs.Segment, []byte) {
t.Helper()
ehdr := eth.DecodeEthernetHeader(b)
if ehdr.AssertType() != eth.EtherTypeIPv4 {
t.Fatalf("not IPv4")
}
ip, ipOffset := eth.DecodeIPv4Header(b[eth.SizeEthernetHeader:])
if ip.Protocol != 6 {
t.Fatalf("not TCP")
}
tcp, tcpOffset := eth.DecodeTCPHeader(b[eth.SizeEthernetHeader+ipOffset:])
offset := eth.SizeEthernetHeader + ipOffset + tcpOffset
end := ip.TotalLength + eth.SizeEthernetHeader
if int(end) > len(b) {
t.Fatalf("bad ip.TotalLength")
}
payload := b[offset:end]
return tcp.Segment(len(payload)), payload
}
func reverseExchange(exchange []seqs.Exchange) []seqs.Exchange {
if len(exchange) == 0 {
panic("len(exchange) != len(states) or empty exchange: " + strconv.Itoa(len(exchange)))
}
firstIsIn := exchange[0].Incoming != nil
if firstIsIn {
panic("please start with an outgoing segment to reverse exchange for best test results")
}
out := make([]seqs.Exchange, len(exchange))
for i := range exchange {
isLast := i == len(exchange)-1
isOut := exchange[i].Outgoing != nil
out[i].WantState, out[i].WantPeerState = exchange[i].WantPeerState, exchange[i].WantState
if isOut {
out[i].Incoming = exchange[i].Outgoing
if !isLast {
out[i].WantPending = exchange[i+1].Incoming
}
} else {
out[i].Outgoing = exchange[i].Incoming
}
}
return out
}
func checkNoPending(t *testing.T, tcb *seqs.ControlBlock) bool {
t.Helper()
// We extensively test the API for inadvertent state modification in a HasPending or PendingSegment call.
hasPD := tcb.HasPending()
pd, ok := tcb.PendingSegment(0)
hasPD2 := tcb.HasPending()
if hasPD || ok || hasPD2 {
t.Errorf("unexpected pending segment: %+v (%v,%v,%v)", pd, hasPD, ok, hasPD2)
return false
}
if hasPD != ok || hasPD != hasPD2 {
t.Fatalf("inconsistent pending segment: (%v,%v,%v)", hasPD, ok, hasPD2)
}
if !ok && pd != (seqs.Segment{}) {
t.Fatalf("inconsistent pending segment: %+v (%v,%v,%v)", pd, hasPD, ok, hasPD2)
}
return true
}
// Full client-server interaction in the sending of "hello world" over TCP in order.
var exchangeHelloWorld = [][]byte{
// client SYN1
0: []byte("\x28\xcd\xc1\x05\x4d\xbb\xd8\x5e\xd3\x43\x03\xeb\x08\x00\x45\x00\x00\x3c\x71\xac\x40\x00\x40\x06\x44\x9b\xc0\xa8\x01\x93\xc0\xa8\x01\x91\x84\x96\x04\xd2\x5e\x72\x2b\x7d\x00\x00\x00\x00\xa0\x02\xfa\xf0\x27\x6d\x00\x00\x02\x04\x05\xb4\x04\x02\x08\x0a\x07\x8b\x86\x4a\x00\x00\x00\x00\x01\x03\x03\x07"),
// server SYNACK
1: []byte("\xd8\x5e\xd3\x43\x03\xeb\x28\xcd\xc1\x05\x4d\xbb\x08\x00\x45\x00\x00\x34\x00\x00\x40\x00\x40\x06\xb6\x4f\xc0\xa8\x01\x91\xc0\xa8\x01\x93\x04\xd2\x84\x96\xbe\x6e\x4c\x0f\x5e\x72\x2b\x7e\x80\x12\x10\x00\xc0\xbb\x00\x00\x02\x04\x05\xb4\x03\x03\x00\x04\x02\x00\x00\x00"),
// client ACK1
2: []byte("\x28\xcd\xc1\x05\x4d\xbb\xd8\x5e\xd3\x43\x03\xeb\x08\x00\x45\x00\x00\x28\x71\xad\x40\x00\x40\x06\x44\xae\xc0\xa8\x01\x93\xc0\xa8\x01\x91\x84\x96\x04\xd2\x5e\x72\x2b\x7e\xbe\x6e\x4c\x10\x50\x10\x01\xf6\x0b\x92\x00\x00"),
// client PSHACK0
3: []byte("\x28\xcd\xc1\x05\x4d\xbb\xd8\x5e\xd3\x43\x03\xeb\x08\x00\x45\x00\x00\x34\x71\xae\x40\x00\x40\x06\x44\xa1\xc0\xa8\x01\x93\xc0\xa8\x01\x91\x84\x96\x04\xd2\x5e\x72\x2b\x7e\xbe\x6e\x4c\x10\x50\x18\x01\xf6\x79\xa5\x00\x00\x68\x65\x6c\x6c\x6f\x20\x77\x6f\x72\x6c\x64\x0a"),
// server ACK1
4: []byte("\xd8\x5e\xd3\x43\x03\xeb\x28\xcd\xc1\x05\x4d\xbb\x08\x00\x45\x00\x00\x28\x00\x00\x40\x00\x40\x06\xb6\x5b\xc0\xa8\x01\x91\xc0\xa8\x01\x93\x04\xd2\x84\x96\xbe\x6e\x4c\x10\x5e\x72\x2b\x8a\x50\x10\x0f\xf4\xfd\x87\x00\x00\x00\x00\x00\x00\x00\x00"),
// server PSHACK1
5: []byte("\xd8\x5e\xd3\x43\x03\xeb\x28\xcd\xc1\x05\x4d\xbb\x08\x00\x45\x00\x00\x34\x00\x00\x40\x00\x40\x06\xb6\x4f\xc0\xa8\x01\x91\xc0\xa8\x01\x93\x04\xd2\x84\x96\xbe\x6e\x4c\x10\x5e\x72\x2b\x8a\x50\x18\x10\x00\x6b\x8f\x00\x00\x68\x65\x6c\x6c\x6f\x20\x77\x6f\x72\x6c\x64\x0a"),
// client ACK2
6: []byte("\x28\xcd\xc1\x05\x4d\xbb\xd8\x5e\xd3\x43\x03\xeb\x08\x00\x45\x00\x00\x28\x71\xaf\x40\x00\x40\x06\x44\xac\xc0\xa8\x01\x93\xc0\xa8\x01\x91\x84\x96\x04\xd2\x5e\x72\x2b\x8a\xbe\x6e\x4c\x1c\x50\x10\x01\xf6\x0b\x7a\x00\x00"),
// client PSHACK1
7: []byte("\x28\xcd\xc1\x05\x4d\xbb\xd8\x5e\xd3\x43\x03\xeb\x08\x00\x45\x00\x00\x34\x71\xb0\x40\x00\x40\x06\x44\x9f\xc0\xa8\x01\x93\xc0\xa8\x01\x91\x84\x96\x04\xd2\x5e\x72\x2b\x8a\xbe\x6e\x4c\x1c\x50\x18\x01\xf6\x79\x8d\x00\x00\x68\x65\x6c\x6c\x6f\x20\x77\x6f\x72\x6c\x64\x0a"),
// server PSHACK2
8: []byte("\xd8\x5e\xd3\x43\x03\xeb\x28\xcd\xc1\x05\x4d\xbb\x08\x00\x45\x00\x00\x34\x00\x00\x40\x00\x40\x06\xb6\x4f\xc0\xa8\x01\x91\xc0\xa8\x01\x93\x04\xd2\x84\x96\xbe\x6e\x4c\x1c\x5e\x72\x2b\x96\x50\x18\x10\x00\x6b\x77\x00\x00\x68\x65\x6c\x6c\x6f\x20\x77\x6f\x72\x6c\x64\x0a"),
// client ACK3
9: []byte("\x28\xcd\xc1\x05\x4d\xbb\xd8\x5e\xd3\x43\x03\xeb\x08\x00\x45\x00\x00\x28\x71\xb1\x40\x00\x40\x06\x44\xaa\xc0\xa8\x01\x93\xc0\xa8\x01\x91\x84\x96\x04\xd2\x5e\x72\x2b\x96\xbe\x6e\x4c\x28\x50\x10\x01\xf6\x0b\x62\x00\x00"),
// client FINACK
10: []byte("\x28\xcd\xc1\x05\x4d\xbb\xd8\x5e\xd3\x43\x03\xeb\x08\x00\x45\x00\x00\x28\x71\xb2\x40\x00\x40\x06\x44\xa9\xc0\xa8\x01\x93\xc0\xa8\x01\x91\x84\x96\x04\xd2\x5e\x72\x2b\x96\xbe\x6e\x4c\x28\x50\x11\x01\xf6\x0b\x61\x00\x00"),
// server ACK
11: []byte("\xd8\x5e\xd3\x43\x03\xeb\x28\xcd\xc1\x05\x4d\xbb\x08\x00\x45\x00\x00\x28\x00\x00\x40\x00\x40\x06\xb6\x5b\xc0\xa8\x01\x91\xc0\xa8\x01\x93\x04\xd2\x84\x96\xbe\x6e\x4c\x28\x5e\x72\x2b\x97\x50\x10\x10\x00\xfd\x56\x00\x00\x00\x00\x00\x00\x00\x00"),
}