Introduce Transport interface

session.go

@@ -1,12 +1,10 @@
 package xmpp
 
 import (
-	"crypto/tls"
 	"encoding/xml"
 	"errors"
 	"fmt"
 	"io"
-	"net"
 
 	"gosrc.io/xmpp/stanza"
 )
@@ -30,35 +28,33 @@ type Session struct {
 	err error
 }
 
-func NewSession(conn net.Conn, o Config, state SMState) (net.Conn, *Session, error) {
+func NewSession(transport Transport, o Config, state SMState) (*Session, error) {
 	s := new(Session)
 	s.SMState = state
-	s.init(conn, o)
+	s.init(transport, o)
 
-	// starttls
-	var tlsConn net.Conn
-	tlsConn = s.startTlsIfSupported(conn, o.parsedJid.Domain, o)
+	s.startTlsIfSupported(transport, o.parsedJid.Domain, o)
 
 	if s.err != nil {
-		return nil, nil, NewConnError(s.err, true)
+		return nil, NewConnError(s.err, true)
 	}
 
 	if !s.TlsEnabled && !o.Insecure {
 		err := fmt.Errorf("failed to negotiate TLS session : %s", s.err)
-		return nil, nil, NewConnError(err, true)
+		return nil, NewConnError(err, true)
 	}
 
 	if s.TlsEnabled {
-		s.reset(conn, tlsConn, o)
+		s.reset(transport, o)
 	}
 
 	// auth
 	s.auth(o)
-	s.reset(tlsConn, tlsConn, o)
+	s.reset(transport, o)
 
 	// attempt resumption
 	if s.resume(o) {
-		return tlsConn, s, s.err
+		return s, s.err
 	}
 
 	// otherwise, bind resource and 'start' XMPP session
@@ -68,7 +64,7 @@ func NewSession(conn net.Conn, o Config, state SMState) (net.Conn, *Session, err
 	// Enable stream management if supported
 	s.EnableStreamManagement(o)
 
-	return tlsConn, s, s.err
+	return s, s.err
 }
 
 func (s *Session) PacketId() string {
@@ -76,24 +72,22 @@ func (s *Session) PacketId() string {
 	return fmt.Sprintf("%x", s.lastPacketId)
 }
 
-func (s *Session) init(conn net.Conn, o Config) {
-	s.setStreamLogger(nil, conn, o)
+func (s *Session) init(transport Transport, o Config) {
+	s.setStreamLogger(transport, o)
 	s.Features = s.open(o.parsedJid.Domain)
 }
 
-func (s *Session) reset(conn net.Conn, newConn net.Conn, o Config) {
+func (s *Session) reset(transport Transport, o Config) {
 	if s.err != nil {
 		return
 	}
 
-	s.setStreamLogger(conn, newConn, o)
+	s.setStreamLogger(transport, o)
 	s.Features = s.open(o.parsedJid.Domain)
 }
 
-func (s *Session) setStreamLogger(conn net.Conn, newConn net.Conn, o Config) {
-	if newConn != conn {
-		s.streamLogger = newStreamLogger(newConn, o.StreamLogger)
-	}
+func (s *Session) setStreamLogger(transport Transport, o Config) {
+	s.streamLogger = newStreamLogger(transport, o.StreamLogger)
 	s.decoder = xml.NewDecoder(s.streamLogger)
 	s.decoder.CharsetReader = o.CharsetReader
 }
@@ -117,9 +111,16 @@ func (s *Session) open(domain string) (f stanza.StreamFeatures) {
 	return
 }
 
-func (s *Session) startTlsIfSupported(conn net.Conn, domain string, o Config) net.Conn {
+func (s *Session) startTlsIfSupported(transport Transport, domain string, o Config) {
 	if s.err != nil {
-		return conn
+		return
+	}
+
+	if !transport.DoesStartTLS() {
+		if !o.Insecure {
+			s.err = errors.New("Transport does not support starttls")
+		}
+		return
 	}
 
 	if _, ok := s.Features.DoesStartTLS(); ok {
@@ -128,39 +129,21 @@ func (s *Session) startTlsIfSupported(conn net.Conn, domain string, o Config) ne
 		var k stanza.TLSProceed
 		if s.err = s.decoder.DecodeElement(&k, nil); s.err != nil {
 			s.err = errors.New("expecting starttls proceed: " + s.err.Error())
-			return conn
+			return
 		}
 
-		if o.TLSConfig == nil {
-			o.TLSConfig = &tls.Config{}
-		}
-
-		if o.TLSConfig.ServerName == "" {
-			o.TLSConfig.ServerName = domain
-		}
-		tlsConn := tls.Client(conn, o.TLSConfig)
-		// We convert existing connection to TLS
-		if s.err = tlsConn.Handshake(); s.err != nil {
-			return tlsConn
-		}
-
-		if !o.TLSConfig.InsecureSkipVerify {
-			s.err = tlsConn.VerifyHostname(domain)
-		}
+		s.err = transport.StartTLS(domain, o)
 
 		if s.err == nil {
 			s.TlsEnabled = true
 		}
-		return tlsConn
+		return
 	}
 
 	// If we do not allow cleartext connections, make it explicit that server do not support starttls
 	if !o.Insecure {
 		s.err = errors.New("XMPP server does not advertise support for starttls")
 	}
-
-	// starttls is not supported => we do not upgrade the connection:
-	return conn
 }
 
 func (s *Session) auth(o Config) {