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Fix flaky packetimpact test 

PiperOrigin-RevId: 355645297
This commit is contained in:
Nayana Bidari 2021-02-04 09:36:09 -08:00 committed by gVisor bot
parent fa2d3698c4
commit eaba5bc7ef
1 changed files with 16 additions and 21 deletions
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37
test/packetimpact/tests/tcp_rack_test.go
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@ -168,9 +168,10 @@ func TestRACKTLPLost(t *testing.T) {
closeSACKConnection(t, dut, conn, acceptFd, listenFd)
}
// TestRACKTLPWithSACK tests TLP by acknowledging out of order packets.
// TestRACKWithSACK tests that RACK marks the packets as lost after receiving
// the ACK for retransmitted packets.
// See: https://tools.ietf.org/html/draft-ietf-tcpm-rack-08#section-8.1
func TestRACKTLPWithSACK(t *testing.T) {
func TestRACKWithSACK(t *testing.T) {
dut, conn, acceptFd, listenFd := createSACKConnection(t)
seqNum1 := *conn.RemoteSeqNum(t)
@ -180,8 +181,9 @@ func TestRACKTLPWithSACK(t *testing.T) {
// We are not sending ACK for these packets.
const numPkts = 3
lastSent := sendAndReceive(t, dut, conn, numPkts, acceptFd, false /* sendACK */)
sendAndReceive(t, dut, conn, numPkts, acceptFd, false /* sendACK */)
time.Sleep(simulatedRTT)
// SACK for #2 packet.
sackBlock := make([]byte, 40)
start := seqNum1.Add(seqnum.Size(payloadSize))
@ -194,32 +196,25 @@ func TestRACKTLPWithSACK(t *testing.T) {
}}, sackBlock[sbOff:])
conn.Send(t, testbench.TCP{Flags: testbench.Uint8(header.TCPFlagAck), AckNum: testbench.Uint32(uint32(seqNum1)), Options: sackBlock[:sbOff]})
// RACK marks #1 packet as lost and retransmits it.
if _, err := conn.Expect(t, testbench.TCP{SeqNum: testbench.Uint32(uint32(seqNum1))}, time.Second); err != nil {
rtt, _ := getRTTAndRTO(t, dut, acceptFd)
timeout := 2 * rtt
// RACK marks #1 packet as lost after RTT+reorderWindow(RTT/4) and
// retransmits it.
if _, err := conn.Expect(t, testbench.TCP{SeqNum: testbench.Uint32(uint32(seqNum1))}, timeout); err != nil {
t.Fatalf("expected payload was not received: %s", err)
}
time.Sleep(simulatedRTT)
// ACK for #1 packet.
conn.Send(t, testbench.TCP{Flags: testbench.Uint8(header.TCPFlagAck), AckNum: testbench.Uint32(uint32(end))})
// Probe Timeout (PTO) should be two times RTT. TLP will trigger for #3
// packet. RACK adds an additional timeout of 200ms if the number of
// outstanding packets is equal to 1.
rtt, rto := getRTTAndRTO(t, dut, acceptFd)
pto := rtt*2 + (200 * time.Millisecond)
if rto < pto {
pto = rto
}
// We expect the 3rd packet (the last unacknowledged packet) to be
// retransmitted.
tlpProbe := testbench.Uint32(uint32(seqNum1) + uint32((numPkts-1)*payloadSize))
if _, err := conn.Expect(t, testbench.TCP{SeqNum: tlpProbe}, time.Second); err != nil {
// RACK considers transmission times of the packets to mark them lost.
// As the 3rd packet was sent before the retransmitted 1st packet, RACK
// marks it as lost and retransmits it..
expectedSeqNum := testbench.Uint32(uint32(seqNum1) + uint32((numPkts-1)*payloadSize))
if _, err := conn.Expect(t, testbench.TCP{SeqNum: expectedSeqNum}, timeout); err != nil {
t.Fatalf("expected payload was not received: %s", err)
}
diff := time.Now().Sub(lastSent)
if diff < pto {
t.Fatalf("expected payload was received before the probe timeout, got: %v, want: %v", diff, pto)
}
closeSACKConnection(t, dut, conn, acceptFd, listenFd)
}