Add support for unix sockets

Author: bigs

convert.go

@@ -3,6 +3,7 @@ package manet
 import (
 	"fmt"
 	"net"
+	"path/filepath"
 
 	ma "github.com/multiformats/go-multiaddr"
 	madns "github.com/multiformats/go-multiaddr-dns"
@@ -61,6 +62,8 @@ func parseBasicNetMaddr(maddr ma.Multiaddr) (net.Addr, error) {
 		return net.ResolveUDPAddr(network, host)
 	case "ip", "ip4", "ip6":
 		return net.ResolveIPAddr(network, host)
+	case "unix":
+		return net.ResolveUnixAddr(network, host)
 	}
 
 	return nil, fmt.Errorf("network not supported: %s", network)
@@ -137,6 +140,10 @@ func DialArgs(m ma.Multiaddr) (string, string, error) {
 				hostname = true
 				ip = c.Value()
 				return true
+			case ma.P_UNIX:
+				network = "unix"
+				ip = c.Value()
+				return false
 			}
 		case "ip4":
 			switch c.Protocol().Code {
@@ -184,6 +191,8 @@ func DialArgs(m ma.Multiaddr) (string, string, error) {
 			return network, ip + ":" + port, nil
 		}
 		return network, "[" + ip + "]" + ":" + port, nil
+	case "unix":
+		return network, ip, nil
 	default:
 		return "", "", fmt.Errorf("%s is not a 'thin waist' address", m)
 	}
@@ -248,3 +257,12 @@ func parseIPPlusNetAddr(a net.Addr) (ma.Multiaddr, error) {
 	}
 	return FromIP(ac.IP)
 }
+
+func parseUnixNetAddr(a net.Addr) (ma.Multiaddr, error) {
+	ac, ok := a.(*net.UnixAddr)
+	if !ok {
+		return nil, errIncorrectNetAddr
+	}
+	cleaned := filepath.Clean(ac.Name)
+	return ma.NewComponent("unix", cleaned)
+}

net.go

@@ -167,7 +167,7 @@ func (d *Dialer) DialContext(ctx context.Context, remote ma.Multiaddr) (Conn, er
 	// ok, Dial!
 	var nconn net.Conn
 	switch rnet {
-	case "tcp", "tcp4", "tcp6", "udp", "udp4", "udp6":
+	case "tcp", "tcp4", "tcp6", "udp", "udp4", "udp6", "unix":
 		nconn, err = d.Dialer.DialContext(ctx, rnet, rnaddr)
 		if err != nil {
 			return nil, err
@@ -178,7 +178,9 @@ func (d *Dialer) DialContext(ctx context.Context, remote ma.Multiaddr) (Conn, er
 
 	// get local address (pre-specified or assigned within net.Conn)
 	local := d.LocalAddr
-	if local == nil {
+	// This block helps us avoid parsing addresses in transports (such as unix
+	// sockets) that don't have local addresses when dialing out.
+	if local == nil && nconn.LocalAddr().String() != "" {
 		local, err = FromNetAddr(nconn.LocalAddr())
 		if err != nil {
 			return nil, err
@@ -243,9 +245,14 @@ func (l *maListener) Accept() (Conn, error) {
 		return nil, err
 	}
 
-	raddr, err := FromNetAddr(nconn.RemoteAddr())
-	if err != nil {
-		return nil, fmt.Errorf("failed to convert connn.RemoteAddr: %s", err)
+	var raddr ma.Multiaddr
+	// This block protects us in transports (i.e. unix sockets) that don't have
+	// remote addresses for inbound connections.
+	if nconn.RemoteAddr().String() != "" {
+		raddr, err = FromNetAddr(nconn.RemoteAddr())
+		if err != nil {
+			return nil, fmt.Errorf("failed to convert conn.RemoteAddr: %s", err)
+		}
 	}
 
 	return wrap(nconn, l.laddr, raddr), nil

net_test.go

@@ -3,9 +3,13 @@ package manet
 import (
 	"bytes"
 	"fmt"
+	"io/ioutil"
 	"net"
+	"os"
+	"path/filepath"
 	"sync"
 	"testing"
+	"time"
 
 	ma "github.com/multiformats/go-multiaddr"
 )
@@ -75,6 +79,62 @@ func TestDial(t *testing.T) {
 	wg.Wait()
 }
 
+func TestUnixSockets(t *testing.T) {
+	dir, err := ioutil.TempDir(os.TempDir(), "manettest")
+	if err != nil {
+		t.Fatal(err)
+	}
+	path := filepath.Join(dir, "listen.sock")
+	maddr := newMultiaddr(t, "/unix/"+path)
+
+	listener, err := Listen(maddr)
+	if err != nil {
+		t.Fatal(err)
+	}
+
+	payload := []byte("hello")
+
+	// listen
+	done := make(chan struct{}, 1)
+	go func() {
+		conn, err := listener.Accept()
+		if err != nil {
+			t.Fatal(err)
+		}
+		defer conn.Close()
+		buf := make([]byte, 1024)
+		n, err := conn.Read(buf)
+		if err != nil {
+			t.Fatal(err)
+		}
+		if n != len(payload) {
+			t.Fatal("failed to read appropriate number of bytes")
+		}
+		if !bytes.Equal(buf[0:n], payload) {
+			t.Fatal("payload did not match")
+		}
+		done <- struct{}{}
+	}()
+
+	// dial
+	conn, err := Dial(maddr)
+	if err != nil {
+		t.Fatal(err)
+	}
+	n, err := conn.Write(payload)
+	if err != nil {
+		t.Fatal(err)
+	}
+	if n != len(payload) {
+		t.Fatal("failed to write appropriate number of bytes")
+	}
+	select {
+	case <-done:
+	case <-time.After(1 * time.Second):
+		t.Fatal("timed out waiting for read")
+	}
+}
+
 func TestListen(t *testing.T) {
 
 	maddr := newMultiaddr(t, "/ip4/127.0.0.1/tcp/4322")

registry.go

@@ -21,8 +21,9 @@ func init() {
 	defaultCodecs.RegisterFromNetAddr(parseUDPNetAddr, "udp", "udp4", "udp6")
 	defaultCodecs.RegisterFromNetAddr(parseIPNetAddr, "ip", "ip4", "ip6")
 	defaultCodecs.RegisterFromNetAddr(parseIPPlusNetAddr, "ip+net")
+	defaultCodecs.RegisterFromNetAddr(parseUnixNetAddr, "unix")
 
-	defaultCodecs.RegisterToNetAddr(parseBasicNetMaddr, "tcp", "udp", "ip6", "ip4")
+	defaultCodecs.RegisterToNetAddr(parseBasicNetMaddr, "tcp", "udp", "ip6", "ip4", "unix")
 }
 
 // CodecMap holds a map of NetCodecs indexed by their Protocol ID