Use go-libutp if cgo is enabled

client.go

@@ -22,7 +22,6 @@ import (
 	"github.com/anacrolix/missinggo/pubsub"
 	"github.com/anacrolix/missinggo/slices"
 	"github.com/anacrolix/sync"
-	"github.com/anacrolix/utp"
 	"github.com/dustin/go-humanize"
 	"golang.org/x/time/rate"
 
@@ -48,7 +47,7 @@ type Client struct {
 	defaultStorage *storage.Client
 	onClose        []func()
 	tcpListener    net.Listener
-	utpSock        *utp.Socket
+	utpSock        utpSocket
 	dHT            *dht.Server
 	ipBlockList    iplist.Ranger
 	// Our BitTorrent protocol extension bytes, sent in our BT handshakes.
@@ -152,15 +151,15 @@ func (cl *Client) WriteStatus(_w io.Writer) {
 	}
 }
 
-func listenUTP(networkSuffix, addr string) (*utp.Socket, error) {
-	return utp.NewSocket("udp"+networkSuffix, addr)
+func listenUTP(networkSuffix, addr string) (utpSocket, error) {
+	return NewUtpSocket("udp"+networkSuffix, addr)
 }
 
 func listenTCP(networkSuffix, addr string) (net.Listener, error) {
 	return net.Listen("tcp"+networkSuffix, addr)
 }
 
-func listenBothSameDynamicPort(networkSuffix, host string) (tcpL net.Listener, utpSock *utp.Socket, listenedAddr string, err error) {
+func listenBothSameDynamicPort(networkSuffix, host string) (tcpL net.Listener, utpSock utpSocket, listenedAddr string, err error) {
 	for {
 		tcpL, err = listenTCP(networkSuffix, net.JoinHostPort(host, "0"))
 		if err != nil {
@@ -179,7 +178,7 @@ func listenBothSameDynamicPort(networkSuffix, host string) (tcpL net.Listener, u
 }
 
 // Listen to enabled protocols, ensuring ports match.
-func listen(tcp, utp bool, networkSuffix, addr string) (tcpL net.Listener, utpSock *utp.Socket, listenedAddr string, err error) {
+func listen(tcp, utp bool, networkSuffix, addr string) (tcpL net.Listener, utpSock utpSocket, listenedAddr string, err error) {
 	if addr == "" {
 		addr = ":50007"
 	}
@@ -341,7 +340,7 @@ func (cl *Client) Close() {
 		cl.dHT.Close()
 	}
 	if cl.utpSock != nil {
-		cl.utpSock.CloseNow()
+		cl.utpSock.Close()
 	}
 	if cl.tcpListener != nil {
 		cl.tcpListener.Close()

client_test.go

@@ -21,7 +21,6 @@ import (
 	"github.com/anacrolix/missinggo"
 	"github.com/anacrolix/missinggo/filecache"
 	"github.com/anacrolix/missinggo/pubsub"
-	"github.com/anacrolix/utp"
 	"github.com/bradfitz/iter"
 	"github.com/stretchr/testify/assert"
 	"github.com/stretchr/testify/require"
@@ -171,7 +170,7 @@ func TestReducedDialTimeout(t *testing.T) {
 }
 
 func TestUTPRawConn(t *testing.T) {
-	l, err := utp.NewSocket("udp", "")
+	l, err := NewUtpSocket("udp", "")
 	if err != nil {
 		t.Fatal(err)
 	}
@@ -185,7 +184,7 @@ func TestUTPRawConn(t *testing.T) {
 		}
 	}()
 	// Connect a UTP peer to see if the RawConn will still work.
-	s, _ := utp.NewSocket("udp", "")
+	s, _ := NewUtpSocket("udp", "")
 	defer s.Close()
 	utpPeer, err := s.Dial(fmt.Sprintf("localhost:%d", missinggo.AddrPort(l.Addr())))
 	if err != nil {

utp.go

@@ -0,0 +1,22 @@
+package torrent
+
+import (
+	"net"
+	"time"
+)
+
+// Abstracts the utp Socket, so the implementation can be selected from
+// different packages.
+type utpSocket interface {
+	Accept() (net.Conn, error)
+	Addr() net.Addr
+	Close() error
+	LocalAddr() net.Addr
+	ReadFrom([]byte) (int, net.Addr, error)
+	SetDeadline(time.Time) error
+	SetWriteDeadline(time.Time) error
+	SetReadDeadline(time.Time) error
+	WriteTo([]byte, net.Addr) (int, error)
+	DialTimeout(string, time.Duration) (net.Conn, error)
+	Dial(string) (net.Conn, error)
+}

utp_go.go

@@ -0,0 +1,11 @@
+// +build !cgo
+
+package torrent
+
+import (
+	"github.com/anacrolix/utp"
+)
+
+func NewUtpSocket(network, addr string) (utpSocket, error) {
+	return utp.NewSocket(network, addr)
+}

utp_libutp.go

@@ -0,0 +1,11 @@
+// +build cgo
+
+package torrent
+
+import (
+	"github.com/anacrolix/go-libutp"
+)
+
+func NewUtpSocket(network, addr string) (utpSocket, error) {
+	return utp.NewSocket(network, addr)
+}