// NewClientServerPipe creates a sandbox communication pipe and attaches a DCCP client and a DCCP
// server to its endpoints. In addition to sending all emits to a standard DCCP log file, it sends a
// copy of all emits to the dup TraceWriter.
func NewClientServerPipe(env *dccp.Env) (clientConn, serverConn *dccp.Conn, clientToServer, serverToClient *headerHalfPipe) {
llog := dccp.NewAmb("line", env)
hca, hcb, _ := NewPipe(env, llog, "client", "server")
ccid := ccid3.CCID3{}
clog := dccp.NewAmb("client", env)
clientConn = dccp.NewConnClient(env, clog, hca, ccid.NewSender(env, clog), ccid.NewReceiver(env, clog), 0)
slog := dccp.NewAmb("server", env)
serverConn = dccp.NewConnServer(env, slog, hcb, ccid.NewSender(env, slog), ccid.NewReceiver(env, slog))
return clientConn, serverConn, hca, hcb
}
// TestRate tests whether a single connection's one-way client-to-server rate converges to
// limit imposed by connection in that the send rate has to:
// (1) converge and stabilize, and
// (2) the stable rate should
// (2.a) either be closely below the connection limit,
// (2.b) or be closely above the connection limit (and maintain a drop rate below some threshold)
// A two-way test is not necessary as the congestion mechanisms in either direction are completely independent.
//
// NOTE: Pipe currently supports rate simulation in packets per time interval. If we want to test behavior
// under variable packet sizes, we need to implement rate simulation in bytes per interval.
func TestRate(t *testing.T) {
env, _ := NewEnv("rate")
clientConn, serverConn, clientToServer, _ := NewClientServerPipe(env)
// Set rate limit on client-to-server connection
clientToServer.SetWriteRate(rateInterval, ratePacketsPerInterval)
cchan := make(chan int, 1)
mtu := clientConn.GetMTU()
buf := make([]byte, mtu)
env.Go(func() {
t0 := env.Now()
for env.Now()-t0 < rateDuration {
err := clientConn.Write(buf)
if err != nil {
t.Errorf("error writing (%s)", err)
break
}
}
// Close is necessary because otherwise, if no read timeout is in place, the
// server sides hangs forever on Read
clientConn.Close()
close(cchan)
}, "test client")
schan := make(chan int, 1)
env.Go(func() {
for {
_, err := serverConn.Read()
if err == dccp.ErrEOF {
break
} else if err != nil {
t.Errorf("error reading (%s)", err)
break
}
}
serverConn.Close()
close(schan)
}, "test server")
_, _ = <-cchan
_, _ = <-schan
clientConn.Abort()
serverConn.Abort()
env.NewGoJoin("end-of-test", clientConn.Joiner(), serverConn.Joiner()).Join()
dccp.NewAmb("line", env).E(dccp.EventMatch, "Server and client done.")
if err := env.Close(); err != nil {
t.Errorf("error closing runtime (%s)", err)
}
}
// Idle keeps the connection between a client and server idle for a few seconds and makes sure that
// no unusual behavior occurs.
func TestIdle(t *testing.T) {
env, _ := NewEnv("idle")
clientConn, serverConn, _, _ := NewClientServerPipe(env)
payload := []byte{1, 2, 3}
cchan := make(chan int, 1)
env.Go(func() {
if err := clientConn.Write(payload); err != nil {
t.Errorf("client write (%s)", err)
}
env.Sleep(10e9) // Stay idle for 10 sec
if err := clientConn.Close(); err != nil && err != dccp.ErrEOF {
t.Errorf("client close (%s)", err)
}
cchan <- 1
close(cchan)
}, "test client")
schan := make(chan int, 1)
env.Go(func() {
if err := serverConn.Write(payload); err != nil {
t.Errorf("server write (%s)", err)
}
env.Sleep(10e9) // Stay idle for 10 sec
if err := serverConn.Close(); err != nil && err != dccp.ErrEOF {
// XXX why not EOF
t.Logf("server close (%s)", err)
}
schan <- 1
close(schan)
}, "test server")
<-cchan
<-schan
clientConn.Abort()
serverConn.Abort()
env.NewGoJoin("end-of-test", clientConn.Joiner(), serverConn.Joiner()).Join()
dccp.NewAmb("line", env).E(dccp.EventMatch, "Server and client done.")
if err := env.Close(); err != nil {
t.Errorf("Error closing runtime (%s)", err)
}
}
// TestOpenClose verifies that connect and close handshakes function correctly
func TestOpenClose(t *testing.T) {
env, _ := NewEnv("openclose")
clientConn, serverConn, _, _ := NewClientServerPipe(env)
cchan := make(chan int, 1)
env.Go(func() {
env.Sleep(2e9)
_, err := clientConn.Read()
if err != dccp.ErrEOF {
t.Errorf("client read error (%s), expected EBADF", err)
}
cchan <- 1
close(cchan)
}, "test client")
schan := make(chan int, 1)
env.Go(func() {
env.Sleep(1e9)
if err := serverConn.Close(); err != nil {
t.Errorf("server close error (%s)", err)
}
schan <- 1
close(schan)
}, "test server")
<-cchan
<-schan
// Abort casuses both connection to wrap up the connection quickly
clientConn.Abort()
serverConn.Abort()
// However, even aborting leaves various connection goroutines lingering for a short while.
// The next line ensures that we wait until all goroutines are done.
env.NewGoJoin("end-of-test", clientConn.Joiner(), serverConn.Joiner()).Join()
dccp.NewAmb("line", env).E(dccp.EventMatch, "Server and client done.")
if err := env.Close(); err != nil {
t.Errorf("Error closing runtime (%s)", err)
}
}
// TestRoundtripEstimation checks that round-trip times are estimated accurately.
func TestRoundtripEstimation(t *testing.T) {
dccp.InstallCtrlCPanic()
env, plex := NewEnv("rtt")
reducer := NewMeasure(env, t)
plex.Add(reducer)
plex.Add(newRoundtripCheckpoint(env, t))
plex.HighlightSamples(ccid3.RoundtripElapsedSample, ccid3.RoundtripReportSample)
clientConn, serverConn, clientToServer, _ := NewClientServerPipe(env)
// Roundtrip estimates might be imprecise during long idle periods,
// as a product of the CCID3 design, since during such period precise
// estimates are not necessary. Therefore, to focus on roundtrip time
// estimation without saturating the link, we generate sufficiently
// regular transmissions.
payload := []byte{1, 2, 3}
buf := make([]byte, len(payload))
// In order to isolate roundtrip measurement testing from the complexities
// of the send rate calculation mechanism, we fix the send rate of both
// endpoints using the debug flag FixRate.
clientConn.Amb().Flags().SetUint32("FixRate", roundtripRate)
serverConn.Amb().Flags().SetUint32("FixRate", roundtripRate)
// Increase the client—>server latency from 0 to latency at half time
env.Go(func() {
env.Sleep(roundtripDuration / 2)
clientToServer.SetWriteLatency(roundtripLatency)
}, "test controller")
cchan := make(chan int, 1)
env.Go(func() {
t0 := env.Now()
for env.Now()-t0 < roundtripDuration {
err := clientConn.Write(buf)
if err != nil {
break
}
}
// Close is necessary because otherwise, if no read timeout is in place, the
// server sides hangs forever on Read
clientConn.Close()
close(cchan)
}, "test client")
schan := make(chan int, 1)
env.Go(func() {
for {
_, err := serverConn.Read()
if err != nil {
break
}
}
close(schan)
}, "test server")
_, _ = <-cchan
_, _ = <-schan
// Shutdown the connections properly
clientConn.Abort()
serverConn.Abort()
env.NewGoJoin("end-of-test", clientConn.Joiner(), serverConn.Joiner()).Join()
dccp.NewAmb("line", env).E(dccp.EventMatch, "Server and client done.")
if err := env.Close(); err != nil {
t.Errorf("error closing runtime (%s)", err)
}
}