fix: Only closing UA should close transport layer

client.go

@@ -81,12 +81,9 @@ func NewClient(ua *UserAgent, options ...ClientOption) (*Client, error) {
 	return c, nil
 }
 
+// Close client handle. UserAgent must be closed for full transaction and transport layer closing.
 func (c *Client) Close() error {
-	// stop transaction layer
-	c.tx.Close()
-
-	// stop transport layer
-	return c.tp.Close()
+	return nil
 }
 
 func (c *Client) GetHostname() string {

server.go

@@ -246,12 +246,9 @@ func (srv *Server) WriteResponse(r *sip.Response) error {
 	return srv.tp.WriteMsg(r)
 }
 
-// Shutdown gracefully shutdowns SIP server
-func (srv *Server) Close() {
-	// stop transaction layer
-	srv.tx.Close()
-	// stop transport layer
-	srv.tp.Close()
+// Close server handle. UserAgent must be closed for full transaction and transport layer closing.
+func (srv *Server) Close() error {
+	return nil
 }
 
 // OnRequest registers new request callback. Can be used as generic way to add handler

sip/transaction.go

@@ -18,6 +18,8 @@ type ServerTransaction interface {
 
 type ClientTransaction interface {
 	Transaction
+	// Responses returns channel with all responses for transaction
 	Responses() <-chan *Response
+	// Cancel sends cancel request
 	Cancel() error
 }

transaction/client_tx.go

@@ -260,5 +260,5 @@ func (tx *ClientTx) delete() {
 		tx.timer_d = nil
 	}
 	tx.mu.Unlock()
-	tx.log.Debug().Str("tx", tx.Key()).Msg("Destroyed")
+	tx.log.Debug().Str("tx", tx.Key()).Msg("Client transaction destroyed")
 }

transaction/server_tx.go

@@ -222,6 +222,7 @@ func (tx *ServerTx) passResp() error {
 }
 
 func (tx *ServerTx) Terminate() {
+	tx.log.Debug().Msg("Server transaction terminating")
 	tx.delete()
 }
 
@@ -253,6 +254,11 @@ func (tx *ServerTx) delete() {
 		close(tx.done)
 		tx.mu.Unlock()
 		tx.onTerminate(tx.key)
+
+		// TODO with ref this can be added, but normally we expect client does closing
+		// if _, err := tx.conn.TryClose(); err != nil {
+		// 	tx.log.Info().Err(err).Msg("Closing connection returned error")
+		// }
 	})
 
 	// time.Sleep(time.Microsecond)
@@ -280,5 +286,5 @@ func (tx *ServerTx) delete() {
 		tx.timer_1xx = nil
 	}
 	tx.mu.Unlock()
-	tx.log.Debug().Str("tx", tx.Key()).Msg("Destroyed")
+	tx.log.Debug().Str("tx", tx.Key()).Msg("Server transaction destroyed")
 }

transport/layer.go

@@ -271,6 +271,9 @@ func (l *Layer) WriteMsgTo(msg sip.Message, addr string, network string) error {
 // ClientRequestConnection is based on
 // https://www.rfc-editor.org/rfc/rfc3261#section-18.1.1
 // It is wrapper for getting and creating connection
+//
+// In case req destination is DNS resolved, destination will be cached or in
+// other words SetDestination will be called
 func (l *Layer) ClientRequestConnection(req *sip.Request) (c Connection, err error) {
 	network := NetworkToLower(req.Transport())
 	transport, ok := l.transports[network]
@@ -293,9 +296,12 @@ func (l *Layer) ClientRequestConnection(req *sip.Request) (c Connection, err err
 	}
 	if raddr.IP == nil {
 		ctx := context.Background()
+		// TODO: how to cache this address, for example reusing in dialog routing
 		if err := l.resolveAddr(ctx, network, host, &raddr); err != nil {
 			return nil, err
 		}
+		// Save destination in request to avoid repeated resolving
+		req.SetDestination(raddr.String())
 	}
 
 	// Now use Via header to determine our local address

transport/udp.go

@@ -29,7 +29,6 @@ var (
 type UDPTransport struct {
 	// listener *net.UDPConn
 	parser *parser.Parser
-	conn   *UDPConnection
 
 	pool      ConnectionPool
 	listeners []*UDPConnection
@@ -40,7 +39,6 @@ type UDPTransport struct {
 func NewUDPTransport(par *parser.Parser) *UDPTransport {
 	p := &UDPTransport{
 		parser: par,
-		conn:   nil, // Making sure interface is nil in returns
 		pool:   NewConnectionPool(),
 	}
 	p.log = log.Logger.With().Str("caller", "transport<UDP>").Logger()
@@ -71,14 +69,6 @@ func (t *UDPTransport) Serve(conn net.PacketConn, handler sip.MessageHandler) er
 
 	c := &UDPConnection{PacketConn: conn}
 
-	// In case single connection avoid pool
-	if len(t.listeners) == 0 {
-		t.conn = c
-	} else {
-		t.conn = nil
-	}
-
-	// t.listenersPool.Add(conn.LocalAddr().String(), c)
 	t.listeners = append(t.listeners, c)
 
 	for i := 0; i < UDPReadWorkers-1; i++ {
@@ -104,10 +94,6 @@ func (t *UDPTransport) GetConnection(addr string) (Connection, error) {
 		return conn, nil
 	}
 
-	if t.conn != nil {
-		return t.conn, nil
-	}
-
 	// TODO: How to pick listener. Some address range mapping
 	if len(t.listeners) > 0 {
 		return t.listeners[0], nil
@@ -160,7 +146,6 @@ func (t *UDPTransport) readConnection(conn *UDPConnection, handler sip.MessageHa
 	defer conn.Close()
 	for {
 		num, raddr, err := conn.ReadFrom(buf)
-
 		if err != nil {
 			if errors.Is(err, net.ErrClosed) {
 				t.log.Debug().Err(err).Msg("Read connection closed")
@@ -293,6 +278,7 @@ func (c *UDPConnection) Close() error {
 	c.mu.Lock()
 	c.refcount = 0
 	c.mu.Unlock()
+	log.Debug().Str("ip", c.LocalAddr().String()).Str("dst", c.Conn.RemoteAddr().String()).Int("ref", 0).Msg("UDP doing hard close")
 	return c.Conn.Close()
 }
 
@@ -315,7 +301,7 @@ func (c *UDPConnection) TryClose() (int, error) {
 		return 0, nil
 	}
 
-	// log.Debug().Str("ip", c.LocalAddr().String()).Str("dst", c.RemoteAddr().String()).Int("ref", ref).Msg("TCP closing")
+	log.Debug().Str("ip", c.LocalAddr().String()).Str("dst", c.Conn.RemoteAddr().String()).Int("ref", ref).Msg("UDP closing")
 	return 0, c.Conn.Close()
 }
 
@@ -373,13 +359,18 @@ func (c *UDPConnection) WriteMsg(msg sip.Message) error {
 	} else {
 		var err error
 
-		dst := msg.Destination()
-		raddr, err := net.ResolveUDPAddr("udp", dst)
+		// TODO lets return this better
+		dst := msg.Destination() // Destination should be already resolved by transport layer
+		host, port, err := sip.ParseAddr(dst)
 		if err != nil {
 			return err
 		}
+		raddr := net.UDPAddr{
+			IP:   net.ParseIP(host),
+			Port: port,
+		}
 
-		n, err = c.WriteTo(data, raddr)
+		n, err = c.WriteTo(data, &raddr)
 		if err != nil {
 			return fmt.Errorf("udp conn %s err. %w", c.PacketConn.LocalAddr().String(), err)
 		}

ua.go

@@ -86,6 +86,14 @@ func NewUA(options ...UserAgentOption) (*UserAgent, error) {
 	return ua, nil
 }
 
+func (ua *UserAgent) Close() error {
+	// stop transaction layer
+	ua.tx.Close()
+
+	// stop transport layer
+	return ua.tp.Close()
+}
+
 // Listen adds listener for serve
 func (ua *UserAgent) setIP(ip net.IP) (err error) {
 	ua.ip = ip