Cleanup the PR a bit

Remove code and simplify some functions. Documentation is still on the
todo.
Also don't export any of these functions and/or types.

server.go

@@ -44,10 +44,10 @@ type response struct {
 	tsigTimersOnly bool
 	tsigRequestMAC string
 	tsigSecret     map[string]string // the tsig secrets
-	udp            *UDPConn          // i/o connection if UDP was used
+	udp            *net.UDPConn      // i/o connection if UDP was used
-	udpSession     *UDPSession
+	tcp            *net.TCPConn      // i/o connection if TCP was used
-	tcp            *net.TCPConn // i/o connection if TCP was used
+	udpSession     *sessionUDP       // oob data to get egress interface right
-	remoteAddr     net.Addr     // address of the client
+	remoteAddr     net.Addr          // address of the client
 }
 
 // ServeMux is an DNS request multiplexer. It matches the
@@ -244,12 +244,10 @@ func (srv *Server) ListenAndServe() error {
 			return e
 		}
 
-		ll, e := NewUDPConn(l)
+		if e := setUDPSocketOptions(l); e != nil {
-		if e != nil {
 			return e
 		}
-
+		return srv.serveUDP(l)
-		return srv.serveUDP(ll)
 	}
 	return &Error{err: "bad network"}
 }
@@ -282,7 +280,7 @@ func (srv *Server) serveTCP(l *net.TCPListener) error {
 
 // serveUDP starts a UDP listener for the server.
 // Each request is handled in a seperate goroutine.
-func (srv *Server) serveUDP(l *UDPConn) error {
+func (srv *Server) serveUDP(l *net.UDPConn) error {
 	defer l.Close()
 	handler := srv.Handler
 	if handler == nil {
@@ -304,7 +302,7 @@ func (srv *Server) serveUDP(l *UDPConn) error {
 }
 
 // Serve a new connection.
-func (srv *Server) serve(a net.Addr, h Handler, m []byte, u *UDPConn, s *UDPSession, t *net.TCPConn) {
+func (srv *Server) serve(a net.Addr, h Handler, m []byte, u *net.UDPConn, s *sessionUDP, t *net.TCPConn) {
 	w := &response{tsigSecret: srv.TsigSecret, udp: u, tcp: t, remoteAddr: a, udpSession: s}
 	q := 0
 Redo:
@@ -392,9 +390,9 @@ func (srv *Server) readTCP(conn *net.TCPConn, timeout time.Duration) ([]byte, er
 	return m, nil
 }
 
-func (srv *Server) readUDP(conn *UDPConn, timeout time.Duration) ([]byte, *UDPSession, error) {
+func (srv *Server) readUDP(conn *net.UDPConn, timeout time.Duration) ([]byte, *sessionUDP, error) {
 	m := make([]byte, srv.UDPSize)
-	n, s, e := conn.ReadFromSessionUDP(m)
+	n, s, e := readFromSessionUDP(conn, m)
 	if e != nil || n == 0 {
 		if e != nil {
 			return nil, nil, e
@@ -430,7 +428,7 @@ func (w *response) WriteMsg(m *Msg) (err error) {
 func (w *response) Write(m []byte) (int, error) {
 	switch {
 	case w.udp != nil:
-		n, err := w.udp.WriteToSessionUDP(m, w.udpSession)
+		n, err := writeToSessionUDP(w.udp, m, w.udpSession)
 		return n, err
 	case w.tcp != nil:
 		lm := len(m)

udp.go

@@ -9,28 +9,19 @@ import (
 	"syscall"
 )
 
-type UDPSession struct {
+type sessionUDP struct {
 	raddr   *net.UDPAddr
 	context []byte
 }
 
-func (session *UDPSession) RemoteAddr() net.Addr {
+func (s *sessionUDP) RemoteAddr() net.Addr { return s.raddr }
-	return session.raddr
-}
 
-// UDPConn wrap a net.UDPConn with dns.UDPConn struct
+// setUDPSocketOptions sets the UDP socket options.
-type UDPConn struct {
+// This function is implemented on a per platform basis. See udp_*.go for more details
-	*net.UDPConn
+func setUDPSocketOptions(conn *net.UDPConn) error {
-}
-
-// NewUDPConn return a new UDPConn.
-// Initialize the underlying net.UDPConn for supporting "sessions"
-// Sessions solve https://github.com/miekg/dns/issues/95
-func NewUDPConn(conn *net.UDPConn) (*UDPConn, error) {
-	// this function is implemented on a per platform basis. See udp_*.go for more details
 	file, err := conn.File()
 	if err != nil {
-		return nil,err
+		return err
 	}
 
 	sa, err := syscall.Getsockname(int(file.Fd()))
@@ -39,34 +30,34 @@ func NewUDPConn(conn *net.UDPConn) (*UDPConn, error) {
 		// dual stack. See http://stackoverflow.com/questions/1618240/how-to-support-both-ipv4-and-ipv6-connections
 		v6only, err := syscall.GetsockoptInt(int(file.Fd()), syscall.IPPROTO_IPV6, syscall.IPV6_V6ONLY)
 		if err != nil {
-			return nil, err
+			return err
 		}
-		SetUDPSocketOptions6(conn)
+		setUDPSocketOptions6(conn)
 
 		if v6only == 0 {
-			SetUDPSocketOptions4(conn)
+			setUDPSocketOptions4(conn)
 		}
 	case *syscall.SockaddrInet4:
-		SetUDPSocketOptions4(conn)
+		setUDPSocketOptions4(conn)
 	}
-	return &UDPConn{conn}, nil
+	return nil
 }
 
-// ReadFromSessionUDP ... Just like net.UDPConn.ReadFrom(), but returns a session object instead of net.UDPAddr
+// readFromSessionUDP ... Just like net.UDPConn.ReadFrom(), but returns a session object instead of net.UDPAddr
 // (RemoteAddr() is available from the UDPSession object)
-func (conn *UDPConn) ReadFromSessionUDP(b []byte) (int, *UDPSession, error) {
+func readFromSessionUDP(conn *net.UDPConn, b []byte) (int, *sessionUDP, error) {
 	oob := make([]byte, 40)
 	n, oobn, _, raddr, err := conn.ReadMsgUDP(b, oob)
 	if err != nil {
 		return n, nil, err
 	}
 
-	session := &UDPSession{raddr, oob[:oobn]}
+	session := &sessionUDP{raddr, oob[:oobn]}
 	return n, session, err
 }
 
-// WriteToSessionUDP Just like net.UDPConn.WritetTo(), but uses a session object instead of net.Addr
+// writeToSessionUDP Just like net.UDPConn.WritetTo(), but uses a session object instead of net.Addr
-func (conn *UDPConn) WriteToSessionUDP(b []byte, session *UDPSession) (int, error) {
+func writeToSessionUDP(conn *net.UDPConn, b []byte, session *sessionUDP) (int, error) {
 	n, _, err := conn.WriteMsgUDP(b, session.context, session.raddr)
 	return n, err
 }

udp_linux.go

@@ -10,7 +10,7 @@ package dns
 // * http://stackoverflow.com/questions/3062205/setting-the-source-ip-for-a-udp-socket and
 // * http://blog.powerdns.com/2012/10/08/on-binding-datagram-udp-sockets-to-the-any-addresses/
 //
-// Why do we need this: When listening on 0.0.0.0 with UDP so kernel decides what is the outoging
+// Why do we need this: When listening on 0.0.0.0 with UDP so kernel decides what is the outgoing
 // interface, this might not always be the correct one. This code will make sure the egress
 // packet's interface matched the ingress' one.
 
@@ -19,9 +19,9 @@ import (
 	"syscall"
 )
 
-// SetUDPSocketOptions4 prepares the v4 socket for sessions.
+// setUDPSocketOptions4 prepares the v4 socket for sessions.
-func SetUDPSocketOptions4(conn *net.UDPConn) error {
+func setUDPSocketOptions4(conn *net.UDPConn) error {
-	// We got the .File() in NewUDPConn, this this will work
+	// We got the .File() in NewUDPConn, this this will work.
 	file, _ := conn.File()
 	err := syscall.SetsockoptInt(int(file.Fd()), syscall.IPPROTO_IP, syscall.IP_PKTINFO, 1)
 	if err != nil {
@@ -30,9 +30,9 @@ func SetUDPSocketOptions4(conn *net.UDPConn) error {
 	return nil
 }
 
-// SetUDPSocketOptions6 prepares the v6 socket for sessions.
+// setUDPSocketOptions6 prepares the v6 socket for sessions.
-func SetUDPSocketOptions6(conn *net.UDPConn) error {
+func setUDPSocketOptions6(conn *net.UDPConn) error {
-	// We got the .File() in NewUDPConn, this this will work
+	// We got the .File() in NewUDPConn, this this will work.
 	file, _ := conn.File()
 	err := syscall.SetsockoptInt(int(file.Fd()), syscall.IPPROTO_IPV6, syscall.IPV6_RECVPKTINFO, 1)
 	if err != nil {

udp_other.go

@@ -12,5 +12,5 @@ import (
 
 // These actually do nothing. See udp_linux.go for an example of how to implement this.
 
-func SetUDPSocketOptions4(conn *net.UDPConn) error { return nil }
+func setUDPSocketOptions4(conn *net.UDPConn) error { return nil }
-func SetUDPSocketOptions6(conn *net.UDPConn) error { return nil }
+func setUDPSocketOptions6(conn *net.UDPConn) error { return nil }