add backdial handshake

sys/backdial/conn.go

@@ -0,0 +1,49 @@
+// Copyright 2015 The Go Circuit Project
+// Use of this source code is governed by the license for
+// The Go Circuit Project, found in the LICENSE file.
+//
+// Authors:
+//   2015 Petar Maymounkov <p@gocircuit.org>
+
+package backdial
+
+import (
+	"encoding/gob"
+	"errors"
+	"github.com/gocircuit/core/sys"
+)
+
+type Welcome struct {
+	Back sys.Addr
+}
+
+func init() {
+	gob.Register(&Welcome{})
+}
+
+type conn struct {
+	back sys.Addr
+	sys.Conn
+}
+
+func (p *peer) handshake(u sys.Conn) (*conn, error) {
+	if err := u.Send(&Welcome{p.Addr()}); err != nil {
+		u.Close()
+		return nil, err
+	}
+	w, err := u.Receive()
+	if err != nil {
+		u.Close()
+		return nil, err
+	}
+	welcome, ok := w.(*Welcome)
+	if !ok {
+		u.Close()
+		return nil, errors.New("protocol")
+	}
+	return &conn{welcome.Back, u}, nil
+}
+
+func (c *conn) Addr() sys.Addr {
+	return c.back
+}

sys/backdial/peer.go

@@ -0,0 +1,40 @@
+// Copyright 2015 The Go Circuit Project
+// Use of this source code is governed by the license for
+// The Go Circuit Project, found in the LICENSE file.
+//
+// Authors:
+//   2015 Petar Maymounkov <p@gocircuit.org>
+
+package backdial
+
+import (
+	"github.com/gocircuit/core/sys"
+)
+
+type peer struct {
+	u sys.Peer
+}
+
+func New(under sys.Peer) sys.Peer {
+	return &peer{under}
+}
+
+func (p *peer) Accept() (sys.Conn, error) {
+	c, err := p.u.Accept()
+	if err != nil {
+		return nil, err
+	}
+	return p.handshake(c)
+}
+
+func (p *peer) Addr() sys.Addr {
+	return p.u.Addr()
+}
+
+func (p *peer) Dial(addr sys.Addr) (conn sys.Conn, err error) {
+	c, err := p.u.Dial(addr)
+	if err != nil {
+		return nil, err
+	}
+	return p.handshake(c)
+}

sys/net/net.go

@@ -0,0 +1,24 @@
+// Copyright 2015 The Go Circuit Project
+// Use of this source code is governed by the license for
+// The Go Circuit Project, found in the LICENSE file.
+//
+// Authors:
+//   2015 Petar Maymounkov <p@gocircuit.org>
+
+package net
+
+import (
+	"github.com/gocircuit/core/sys"
+	"io"
+)
+
+type Peer interface {
+	Dial(addr sys.Addr) (Conn, error)
+	Accept() (Conn, error)
+	Addr() sys.Addr
+}
+
+type Conn interface {
+	io.ReadWriteCloser
+	Addr() sys.Addr
+}

sys/sandbox/conn.go

@@ -1,9 +1,9 @@
-// Copyright 2013 Tumblr, Inc.
+// Copyright 2015 The Go Circuit Project
 // Use of this source code is governed by the license for
 // The Go Circuit Project, found in the LICENSE file.
 //
 // Authors:
-//   2013 Petar Maymounkov <p@gocircuit.org>
+//   2015 Petar Maymounkov <p@gocircuit.org>
 
 package sandbox