p2p: Add NodeDialer interface

Signed-off-by: Lewis Marshall <lewis@lmars.net>

p2p/dial.go

@@ -47,6 +47,24 @@ const (
 	maxResolveDelay     = time.Hour
 )
 
+// NodeDialer is used to connect to nodes in the network, typically by using
+// an underlying net.Dialer but also using net.Pipe in tests
+type NodeDialer interface {
+	Dial(*discover.Node) (net.Conn, error)
+}
+
+// TCPDialer implements the NodeDialer interface by using a net.Dialer to
+// create TCP connections to nodes in the network
+type TCPDialer struct {
+	*net.Dialer
+}
+
+// Dial creates a TCP connection to the node
+func (t TCPDialer) Dial(dest *discover.Node) (net.Conn, error) {
+	addr := &net.TCPAddr{IP: dest.IP, Port: int(dest.TCP)}
+	return t.Dialer.Dial("tcp", addr.String())
+}
+
 // dialstate schedules dials and discovery lookups.
 // it get's a chance to compute new tasks on every iteration
 // of the main loop in Server.run.
@@ -318,8 +336,7 @@ func (t *dialTask) resolve(srv *Server) bool {
 
 // dial performs the actual connection attempt.
 func (t *dialTask) dial(srv *Server, dest *discover.Node) bool {
-	addr := &net.TCPAddr{IP: dest.IP, Port: int(dest.TCP)}
-	fd, err := srv.Dialer.Dial("tcp", addr.String())
+	fd, err := srv.Dialer.Dial(dest)
 	if err != nil {
 		log.Trace("Dial error", "task", t, "err", err)
 		return false

p2p/dial_test.go

@@ -597,7 +597,7 @@ func TestDialResolve(t *testing.T) {
 	}
 
 	// Now run the task, it should resolve the ID once.
-	config := Config{Dialer: &net.Dialer{Deadline: time.Now().Add(-5 * time.Minute)}}
+	config := Config{Dialer: TCPDialer{&net.Dialer{Deadline: time.Now().Add(-5 * time.Minute)}}}
 	srv := &Server{ntab: table, Config: config}
 	tasks[0].Do(srv)
 	if !reflect.DeepEqual(table.resolveCalls, []discover.NodeID{dest.ID}) {

p2p/server.go

@@ -131,7 +131,7 @@ type Config struct {
 
 	// If Dialer is set to a non-nil value, the given Dialer
 	// is used to dial outbound peer connections.
-	Dialer *net.Dialer `toml:"-"`
+	Dialer NodeDialer `toml:"-"`
 
 	// If NoDial is true, the server will not dial any peers.
 	NoDial bool `toml:",omitempty"`
@@ -369,7 +369,7 @@ func (srv *Server) Start() (err error) {
 		srv.newTransport = newRLPX
 	}
 	if srv.Dialer == nil {
-		srv.Dialer = &net.Dialer{Timeout: defaultDialTimeout}
+		srv.Dialer = TCPDialer{&net.Dialer{Timeout: defaultDialTimeout}}
 	}
 	srv.quit = make(chan struct{})
 	srv.addpeer = make(chan *conn)