add proxy proto support

obfsshd/proxy_protocol.go

@@ -0,0 +1,50 @@
+package main
+
+import (
+	"bufio"
+	"net"
+
+	proxyproto "github.com/pires/go-proxyproto"
+)
+
+type protoListener struct {
+	net.Listener
+}
+
+type protoConn struct {
+	net.Conn
+	headerDone bool
+	r          *bufio.Reader
+	proxy      *proxyproto.Header
+}
+
+func (l *protoListener) Accept() (net.Conn, error) {
+	c, err := l.Listener.Accept()
+	if err != nil {
+		return nil, err
+	}
+	return &protoConn{Conn: c}, err
+}
+
+func (c *protoConn) Read(buf []byte) (int, error) {
+	var err error
+	if !c.headerDone {
+		c.r = bufio.NewReader(c.Conn)
+		c.proxy, err = proxyproto.Read(c.r)
+		if err != nil && err != proxyproto.ErrNoProxyProtocol {
+			return 0, err
+		}
+		c.headerDone = true
+		return c.r.Read(buf)
+	}
+	return c.r.Read(buf)
+}
+
+func (c *protoConn) RemoteAddr() net.Addr {
+	if c.proxy == nil {
+		return c.Conn.RemoteAddr()
+	}
+	return &net.TCPAddr{
+		IP:   c.proxy.SourceAddress,
+		Port: int(c.proxy.SourcePort)}
+}

obfsshd/server.go

@@ -115,22 +115,22 @@ func main() {
 		go func(lst listen) {
 			var l net.Listener
 			var err error
-			if lst.Key == "" || lst.Cert == "" {
+
 			l, err = net.Listen("tcp", fmt.Sprintf(":%d", lst.Port))
-			} else {
-				cert, err := tls.LoadX509KeyPair(lst.Cert, lst.Key)
 			if err != nil {
 				log.Fatal(err)
 			}
-				l, err = tls.Listen("tcp", fmt.Sprintf(":%d", lst.Port), &tls.Config{
-					Certificates: []tls.Certificate{cert},
-				})
-			}
+			defer l.Close()
 
+			if lst.Key != "" && lst.Cert != "" {
+				cert, err := tls.LoadX509KeyPair(lst.Cert, lst.Key)
 				if err != nil {
 					log.Fatal(err)
 				}
-			defer l.Close()
+				l = tls.NewListener(&protoListener{l}, &tls.Config{
+					Certificates: []tls.Certificate{cert},
+				})
+			}
 
 			for {
 				c, err := l.Accept()