proxy: rename to Proxy, refactor initialization (#4921)

* proxy: rename to Proxy, refactor initialization

* improve documentation

integrationtests/tools/proxy/proxy_test.go

@@ -1,11 +1,8 @@
 package quicproxy
 
 import (
-	"bytes"
 	"net"
-	"runtime/pprof"
 	"strconv"
-	"strings"
 	"sync/atomic"
 	"testing"
 	"time"
@@ -16,6 +13,14 @@ import (
 	"github.com/stretchr/testify/require"
 )
 
+func newUPDConnLocalhost(t testing.TB) *net.UDPConn {
+	t.Helper()
+	conn, err := net.ListenUDP("udp", &net.UDPAddr{IP: net.IPv4(127, 0, 0, 1), Port: 0})
+	require.NoError(t, err)
+	t.Cleanup(func() { conn.Close() })
+	return conn
+}
+
 type packetData []byte
 
 func makePacket(t *testing.T, p protocol.PacketNumber, payload []byte) []byte {
@@ -47,37 +52,6 @@ func readPacketNumber(t *testing.T, b []byte) protocol.PacketNumber {
 	return extHdr.PacketNumber
 }
 
-func TestProxyShutdown(t *testing.T) {
-	isProxyRunning := func() bool {
-		var b bytes.Buffer
-		pprof.Lookup("goroutine").WriteTo(&b, 1)
-		return strings.Contains(b.String(), "proxy.(*QuicProxy).runProxy")
-	}
-
-	proxy, err := NewQuicProxy("localhost:0", nil)
-	require.NoError(t, err)
-	require.Eventually(t, func() bool { return isProxyRunning() }, time.Second, 10*time.Millisecond)
-
-	conn, err := net.DialUDP("udp", nil, proxy.LocalAddr().(*net.UDPAddr))
-	require.NoError(t, err)
-	_, err = conn.Write(makePacket(t, 1, []byte("foobar")))
-	require.NoError(t, err)
-
-	require.NoError(t, proxy.Close())
-
-	// check that the proxy port is not in use anymore
-	// sometimes it takes a while for the OS to free the port
-	require.Eventually(t, func() bool {
-		ln, err := net.ListenUDP("udp", proxy.LocalAddr().(*net.UDPAddr))
-		if err != nil {
-			return false
-		}
-		ln.Close()
-		return true
-	}, time.Second, 10*time.Millisecond)
-	require.Eventually(t, func() bool { return !isProxyRunning() }, time.Second, 10*time.Millisecond)
-}
-
 // Set up a dumb UDP server.
 // In production this would be a QUIC server.
 func runServer(t *testing.T) (*net.UDPAddr, chan packetData) {
@@ -116,25 +90,19 @@ func runServer(t *testing.T) (*net.UDPAddr, chan packetData) {
 	return serverConn.LocalAddr().(*net.UDPAddr), serverReceivedPackets
 }
 
-func startProxy(t *testing.T, opts *Opts) (clientConn *net.UDPConn) {
-	proxy, err := NewQuicProxy("localhost:0", opts)
-	require.NoError(t, err)
-	clientConn, err = net.DialUDP("udp", nil, proxy.LocalAddr().(*net.UDPAddr))
-	require.NoError(t, err)
-
-	t.Cleanup(func() {
-		require.NoError(t, proxy.Close())
-		require.NoError(t, clientConn.Close())
-	})
-	return clientConn
-}
-
 func TestProxyyingBackAndForth(t *testing.T) {
 	serverAddr, _ := runServer(t)
-	clientConn := startProxy(t, &Opts{RemoteAddr: serverAddr.String()})
+	proxy := Proxy{
+		Conn:       newUPDConnLocalhost(t),
+		ServerAddr: serverAddr,
+	}
+	require.NoError(t, proxy.Start())
+	defer proxy.Close()
+	clientConn, err := net.DialUDP("udp", nil, proxy.LocalAddr().(*net.UDPAddr))
+	require.NoError(t, err)
 
 	// send the first packet
-	_, err := clientConn.Write(makePacket(t, 1, []byte("foobar")))
+	_, err = clientConn.Write(makePacket(t, 1, []byte("foobar")))
 	require.NoError(t, err)
 	// send the second packet
 	_, err = clientConn.Write(makePacket(t, 2, []byte("decafbad")))
@@ -153,15 +121,20 @@ func TestDropIncomingPackets(t *testing.T) {
 	const numPackets = 6
 	serverAddr, serverReceivedPackets := runServer(t)
 	var counter atomic.Int32
-	clientConn := startProxy(t, &Opts{
-		RemoteAddr: serverAddr.String(),
+	proxy := Proxy{
+		Conn:       newUPDConnLocalhost(t),
+		ServerAddr: serverAddr,
 		DropPacket: func(d Direction, _ []byte) bool {
 			if d != DirectionIncoming {
 				return false
 			}
 			return counter.Add(1)%2 == 1
 		},
-	})
+	}
+	require.NoError(t, proxy.Start())
+	defer proxy.Close()
+	clientConn, err := net.DialUDP("udp", nil, proxy.LocalAddr().(*net.UDPAddr))
+	require.NoError(t, err)
 
 	for i := 1; i <= numPackets; i++ {
 		_, err := clientConn.Write(makePacket(t, protocol.PacketNumber(i), []byte("foobar"+strconv.Itoa(i))))
@@ -186,15 +159,20 @@ func TestDropOutgoingPackets(t *testing.T) {
 	const numPackets = 6
 	serverAddr, serverReceivedPackets := runServer(t)
 	var counter atomic.Int32
-	clientConn := startProxy(t, &Opts{
-		RemoteAddr: serverAddr.String(),
+	proxy := Proxy{
+		Conn:       newUPDConnLocalhost(t),
+		ServerAddr: serverAddr,
 		DropPacket: func(d Direction, _ []byte) bool {
 			if d != DirectionOutgoing {
 				return false
 			}
 			return counter.Add(1)%2 == 1
 		},
-	})
+	}
+	require.NoError(t, proxy.Start())
+	defer proxy.Close()
+	clientConn, err := net.DialUDP("udp", nil, proxy.LocalAddr().(*net.UDPAddr))
+	require.NoError(t, err)
 
 	clientReceivedPackets := make(chan struct{}, numPackets)
 	// receive the packets echoed by the server on client side
@@ -234,19 +212,24 @@ func TestDelayIncomingPackets(t *testing.T) {
 	const delay = 200 * time.Millisecond
 	serverAddr, serverReceivedPackets := runServer(t)
 	var counter atomic.Int32
-	clientConn := startProxy(t, &Opts{
-		RemoteAddr: serverAddr.String(),
-		// delay packet 1 by 200 ms
-		// delay packet 2 by 400 ms
-		// ...
+	proxy := Proxy{
+		Conn:       newUPDConnLocalhost(t),
+		ServerAddr: serverAddr,
 		DelayPacket: func(d Direction, _ []byte) time.Duration {
+			// delay packet 1 by 200 ms
+			// delay packet 2 by 400 ms
+			// ...
 			if d == DirectionOutgoing {
 				return 0
 			}
 			p := counter.Add(1)
 			return time.Duration(p) * delay
 		},
-	})
+	}
+	require.NoError(t, proxy.Start())
+	defer proxy.Close()
+	clientConn, err := net.DialUDP("udp", nil, proxy.LocalAddr().(*net.UDPAddr))
+	require.NoError(t, err)
 
 	start := time.Now()
 	for i := 1; i <= numPackets; i++ {
@@ -276,19 +259,24 @@ func TestPacketReordering(t *testing.T) {
 
 	serverAddr, serverReceivedPackets := runServer(t)
 	var counter atomic.Int32
-	clientConn := startProxy(t, &Opts{
-		RemoteAddr: serverAddr.String(),
-		// delay packet 1 by 600 ms
-		// delay packet 2 by 400 ms
-		// delay packet 3 by 200 ms
+	proxy := Proxy{
+		Conn:       newUPDConnLocalhost(t),
+		ServerAddr: serverAddr,
 		DelayPacket: func(d Direction, _ []byte) time.Duration {
+			// delay packet 1 by 600 ms
+			// delay packet 2 by 400 ms
+			// delay packet 3 by 200 ms
 			if d == DirectionOutgoing {
 				return 0
 			}
 			p := counter.Add(1)
 			return 600*time.Millisecond - time.Duration(p-1)*delay
 		},
-	})
+	}
+	require.NoError(t, proxy.Start())
+	defer proxy.Close()
+	clientConn, err := net.DialUDP("udp", nil, proxy.LocalAddr().(*net.UDPAddr))
+	require.NoError(t, err)
 
 	// send 3 packets
 	start := time.Now()
@@ -310,15 +298,20 @@ func TestPacketReordering(t *testing.T) {
 
 func TestConstantDelay(t *testing.T) { // no reordering expected here
 	serverAddr, serverReceivedPackets := runServer(t)
-	clientConn := startProxy(t, &Opts{
-		RemoteAddr: serverAddr.String(),
+	proxy := Proxy{
+		Conn:       newUPDConnLocalhost(t),
+		ServerAddr: serverAddr,
 		DelayPacket: func(d Direction, _ []byte) time.Duration {
 			if d == DirectionOutgoing {
 				return 0
 			}
 			return 100 * time.Millisecond
 		},
-	})
+	}
+	require.NoError(t, proxy.Start())
+	defer proxy.Close()
+	clientConn, err := net.DialUDP("udp", nil, proxy.LocalAddr().(*net.UDPAddr))
+	require.NoError(t, err)
 
 	// send 100 packets
 	for i := 0; i < 100; i++ {
@@ -343,19 +336,24 @@ func TestDelayOutgoingPackets(t *testing.T) {
 
 	serverAddr, serverReceivedPackets := runServer(t)
 	var counter atomic.Int32
-	clientConn := startProxy(t, &Opts{
-		RemoteAddr: serverAddr.String(),
-		// delay packet 1 by 200 ms
-		// delay packet 2 by 400 ms
-		// ...
+	proxy := Proxy{
+		Conn:       newUPDConnLocalhost(t),
+		ServerAddr: serverAddr,
 		DelayPacket: func(d Direction, _ []byte) time.Duration {
+			// delay packet 1 by 200 ms
+			// delay packet 2 by 400 ms
+			// ...
 			if d == DirectionIncoming {
 				return 0
 			}
 			p := counter.Add(1)
 			return time.Duration(p) * delay
 		},
-	})
+	}
+	require.NoError(t, proxy.Start())
+	defer proxy.Close()
+	clientConn, err := net.DialUDP("udp", nil, proxy.LocalAddr().(*net.UDPAddr))
+	require.NoError(t, err)
 
 	clientReceivedPackets := make(chan packetData, numPackets)
 	// receive the packets echoed by the server on client side