Merge pull request #1459 from libp2p/merge-reuseport

move go-reuseport-transport here

go.mod

@@ -30,7 +30,6 @@ require (
 	github.com/libp2p/go-msgio v0.2.0
 	github.com/libp2p/go-netroute v0.2.0
 	github.com/libp2p/go-reuseport v0.1.0
-	github.com/libp2p/go-reuseport-transport v0.1.0
 	github.com/libp2p/go-stream-muxer-multistream v0.4.0
 	github.com/libp2p/go-yamux/v3 v3.1.1
 	github.com/libp2p/zeroconf/v2 v2.1.1

p2p/net/reuseport/dial.go

@@ -0,0 +1,113 @@
+package reuseport
+
+import (
+	"context"
+	"net"
+
+	"github.com/libp2p/go-reuseport"
+	ma "github.com/multiformats/go-multiaddr"
+	manet "github.com/multiformats/go-multiaddr/net"
+)
+
+type dialer interface {
+	Dial(network, addr string) (net.Conn, error)
+	DialContext(ctx context.Context, network, addr string) (net.Conn, error)
+}
+
+// Dial dials the given multiaddr, reusing ports we're currently listening on if
+// possible.
+//
+// Dial attempts to be smart about choosing the source port. For example, If
+// we're dialing a loopback address and we're listening on one or more loopback
+// ports, Dial will randomly choose one of the loopback ports and addresses and
+// reuse it.
+func (t *Transport) Dial(raddr ma.Multiaddr) (manet.Conn, error) {
+	return t.DialContext(context.Background(), raddr)
+}
+
+// DialContext is like Dial but takes a context.
+func (t *Transport) DialContext(ctx context.Context, raddr ma.Multiaddr) (manet.Conn, error) {
+	network, addr, err := manet.DialArgs(raddr)
+	if err != nil {
+		return nil, err
+	}
+	var d dialer
+	switch network {
+	case "tcp4":
+		d = t.v4.getDialer(network)
+	case "tcp6":
+		d = t.v6.getDialer(network)
+	default:
+		return nil, ErrWrongProto
+	}
+	conn, err := d.DialContext(ctx, network, addr)
+	if err != nil {
+		return nil, err
+	}
+	maconn, err := manet.WrapNetConn(conn)
+	if err != nil {
+		conn.Close()
+		return nil, err
+	}
+	return maconn, nil
+}
+
+func (n *network) getDialer(network string) dialer {
+	n.mu.RLock()
+	d := n.dialer
+	n.mu.RUnlock()
+	if d == nil {
+		n.mu.Lock()
+		defer n.mu.Unlock()
+
+		if n.dialer == nil {
+			n.dialer = n.makeDialer(network)
+		}
+		d = n.dialer
+	}
+	return d
+}
+
+func (n *network) makeDialer(network string) dialer {
+	if !reuseport.Available() {
+		log.Debug("reuseport not available")
+		return &net.Dialer{}
+	}
+
+	var unspec net.IP
+	switch network {
+	case "tcp4":
+		unspec = net.IPv4zero
+	case "tcp6":
+		unspec = net.IPv6unspecified
+	default:
+		panic("invalid network: must be either tcp4 or tcp6")
+	}
+
+	// How many ports are we listening on.
+	var port = 0
+	for l := range n.listeners {
+		newPort := l.Addr().(*net.TCPAddr).Port
+		switch {
+		case newPort == 0: // Any port, ignore (really, we shouldn't get this case...).
+		case port == 0: // Haven't selected a port yet, choose this one.
+			port = newPort
+		case newPort == port: // Same as the selected port, continue...
+		default: // Multiple ports, use the multi dialer
+			return newMultiDialer(unspec, n.listeners)
+		}
+	}
+
+	// None.
+	if port == 0 {
+		return &net.Dialer{}
+	}
+
+	// One. Always dial from the single port we're listening on.
+	laddr := &net.TCPAddr{
+		IP:   unspec,
+		Port: port,
+	}
+
+	return (*singleDialer)(laddr)
+}

p2p/net/reuseport/listen.go

@@ -0,0 +1,80 @@
+package reuseport
+
+import (
+	"net"
+
+	"github.com/libp2p/go-reuseport"
+	ma "github.com/multiformats/go-multiaddr"
+	manet "github.com/multiformats/go-multiaddr/net"
+)
+
+type listener struct {
+	manet.Listener
+	network *network
+}
+
+func (l *listener) Close() error {
+	l.network.mu.Lock()
+	delete(l.network.listeners, l)
+	l.network.dialer = nil
+	l.network.mu.Unlock()
+	return l.Listener.Close()
+}
+
+// Listen listens on the given multiaddr.
+//
+// If reuseport is supported, it will be enabled for this listener and future
+// dials from this transport may reuse the port.
+//
+// Note: You can listen on the same multiaddr as many times as you want
+// (although only *one* listener will end up handling the inbound connection).
+func (t *Transport) Listen(laddr ma.Multiaddr) (manet.Listener, error) {
+	nw, naddr, err := manet.DialArgs(laddr)
+	if err != nil {
+		return nil, err
+	}
+	var n *network
+	switch nw {
+	case "tcp4":
+		n = &t.v4
+	case "tcp6":
+		n = &t.v6
+	default:
+		return nil, ErrWrongProto
+	}
+
+	if !reuseport.Available() {
+		return manet.Listen(laddr)
+	}
+	nl, err := reuseport.Listen(nw, naddr)
+	if err != nil {
+		return manet.Listen(laddr)
+	}
+
+	if _, ok := nl.Addr().(*net.TCPAddr); !ok {
+		nl.Close()
+		return nil, ErrWrongProto
+	}
+
+	malist, err := manet.WrapNetListener(nl)
+	if err != nil {
+		nl.Close()
+		return nil, err
+	}
+
+	list := &listener{
+		Listener: malist,
+		network:  n,
+	}
+
+	n.mu.Lock()
+	defer n.mu.Unlock()
+
+	if n.listeners == nil {
+		n.listeners = make(map[*listener]struct{})
+	}
+	n.listeners[list] = struct{}{}
+	n.dialer = nil
+
+	return list, nil
+}

p2p/net/reuseport/multidialer.go

@@ -0,0 +1,90 @@
+package reuseport
+
+import (
+	"context"
+	"fmt"
+	"math/rand"
+	"net"
+
+	"github.com/libp2p/go-netroute"
+)
+
+type multiDialer struct {
+	listeningAddresses []*net.TCPAddr
+	loopback           []*net.TCPAddr
+	unspecified        []*net.TCPAddr
+	fallback           net.TCPAddr
+}
+
+func (d *multiDialer) Dial(network, addr string) (net.Conn, error) {
+	return d.DialContext(context.Background(), network, addr)
+}
+
+func randAddr(addrs []*net.TCPAddr) *net.TCPAddr {
+	if len(addrs) > 0 {
+		return addrs[rand.Intn(len(addrs))]
+	}
+	return nil
+}
+
+// DialContext dials a target addr.
+// Dialing preference is
+// * If there is a listener on the local interface the OS expects to use to route towards addr, use that.
+// * If there is a listener on a loopback address, addr is loopback, use that.
+// * If there is a listener on an undefined address (0.0.0.0 or ::), use that.
+// * Use the fallback IP specified during construction, with a port that's already being listened on, if one exists.
+func (d *multiDialer) DialContext(ctx context.Context, network, addr string) (net.Conn, error) {
+	tcpAddr, err := net.ResolveTCPAddr(network, addr)
+	if err != nil {
+		return nil, err
+	}
+	ip := tcpAddr.IP
+	if !ip.IsLoopback() && !ip.IsGlobalUnicast() {
+		return nil, fmt.Errorf("undialable IP: %s", ip)
+	}
+
+	if router, err := netroute.New(); err == nil {
+		if _, _, preferredSrc, err := router.Route(ip); err == nil {
+			for _, optAddr := range d.listeningAddresses {
+				if optAddr.IP.Equal(preferredSrc) {
+					return reuseDial(ctx, optAddr, network, addr)
+				}
+			}
+		}
+	}
+
+	if ip.IsLoopback() && len(d.loopback) > 0 {
+		return reuseDial(ctx, randAddr(d.loopback), network, addr)
+	}
+	if len(d.unspecified) == 0 {
+		return reuseDial(ctx, &d.fallback, network, addr)
+	}
+
+	return reuseDial(ctx, randAddr(d.unspecified), network, addr)
+}
+
+func newMultiDialer(unspec net.IP, listeners map[*listener]struct{}) (m dialer) {
+	addrs := make([]*net.TCPAddr, 0)
+	loopback := make([]*net.TCPAddr, 0)
+	unspecified := make([]*net.TCPAddr, 0)
+	existingPort := 0
+
+	for l := range listeners {
+		addr := l.Addr().(*net.TCPAddr)
+		addrs = append(addrs, addr)
+		if addr.IP.IsLoopback() {
+			loopback = append(loopback, addr)
+		} else if addr.IP.IsGlobalUnicast() && existingPort == 0 {
+			existingPort = addr.Port
+		} else if addr.IP.IsUnspecified() {
+			unspecified = append(unspecified, addr)
+		}
+	}
+	m = &multiDialer{
+		listeningAddresses: addrs,
+		loopback:           loopback,
+		unspecified:        unspecified,
+		fallback:           net.TCPAddr{IP: unspec, Port: existingPort},
+	}
+	return
+}

p2p/net/reuseport/reuseport.go

@@ -0,0 +1,35 @@
+package reuseport
+
+import (
+	"context"
+	"net"
+
+	"github.com/libp2p/go-reuseport"
+)
+
+var fallbackDialer net.Dialer
+
+// Dials using reuseport and then redials normally if that fails.
+func reuseDial(ctx context.Context, laddr *net.TCPAddr, network, raddr string) (con net.Conn, err error) {
+	if laddr == nil {
+		return fallbackDialer.DialContext(ctx, network, raddr)
+	}
+
+	d := net.Dialer{
+		LocalAddr: laddr,
+		Control:   reuseport.Control,
+	}
+
+	con, err = d.DialContext(ctx, network, raddr)
+	if err == nil {
+		return con, nil
+	}
+
+	if reuseErrShouldRetry(err) && ctx.Err() == nil {
+		// We could have an existing socket open or we could have one
+		// stuck in TIME-WAIT.
+		log.Debugf("failed to reuse port, will try again with a random port: %s", err)
+		con, err = fallbackDialer.DialContext(ctx, network, raddr)
+	}
+	return con, err
+}

p2p/net/reuseport/reuseport_plan9.go

@@ -0,0 +1,44 @@
+package reuseport
+
+import (
+	"net"
+	"os"
+)
+
+const (
+	EADDRINUSE   = "address in use"
+	ECONNREFUSED = "connection refused"
+)
+
+// reuseErrShouldRetry diagnoses whether to retry after a reuse error.
+// if we failed to bind, we should retry. if bind worked and this is a
+// real dial error (remote end didnt answer) then we should not retry.
+func reuseErrShouldRetry(err error) bool {
+	if err == nil {
+		return false // hey, it worked! no need to retry.
+	}
+
+	// if it's a network timeout error, it's a legitimate failure.
+	if nerr, ok := err.(net.Error); ok && nerr.Timeout() {
+		return false
+	}
+
+	e, ok := err.(*net.OpError)
+	if !ok {
+		return true
+	}
+
+	e1, ok := e.Err.(*os.PathError)
+	if !ok {
+		return true
+	}
+
+	switch e1.Err.Error() {
+	case EADDRINUSE:
+		return true
+	case ECONNREFUSED:
+		return false
+	default:
+		return true // optimistically default to retry.
+	}
+}