add tls dialer

client.go

@@ -56,13 +56,13 @@ func (c *Client) exchange(ctx context.Context, req, resp *Message) error {
 
 	_, err = conn.Write(req.Raw)
 	if err != nil {
-		return nil
+		return err
 	}
 
 	resp.Raw = resp.Raw[:cap(resp.Raw)]
 	n, err := conn.Read(resp.Raw)
 	if err != nil {
-		return nil
+		return err
 	}
 
 	resp.Raw = resp.Raw[:n]

client_dialer.go

@@ -2,6 +2,7 @@ package fastdns
 
 import (
 	"context"
+	"crypto/tls"
 	"fmt"
 	"io"
 	"net"
@@ -66,6 +67,61 @@ func (d *UDPDialer) put(conn net.Conn) {
 	d.conns <- conn
 }
 
+// TLSDialer is a custom dialer for creating TLS connections.
+// It manages a pool of connections to optimize performance in scenarios
+// where multiple TLS connections to the same server are required.
+type TLSDialer struct {
+	// Addr specifies the remote TLS address that the dialer will connect to.
+	Addr *net.TCPAddr
+
+	TLSConfig *tls.Config
+
+	// Timeout specifies the maximum duration for a query to complete.
+	// If a query exceeds this duration, it will result in a timeout error.
+	Timeout time.Duration
+
+	// MaxConns limits the maximum number of TLS connections that can be created
+	// and reused. Once this limit is reached, no new connections will be made.
+	// If not set, use 64 as default.
+	MaxConns uint16
+
+	once  sync.Once
+	conns chan net.Conn
+}
+
+func (d *TLSDialer) DialContext(ctx context.Context, network, addr string) (conn net.Conn, err error) {
+	return d.get()
+}
+
+func (d *TLSDialer) get() (_ net.Conn, err error) {
+	d.once.Do(func() {
+		if d.MaxConns == 0 {
+			d.MaxConns = 64
+		}
+		d.conns = make(chan net.Conn, d.MaxConns)
+		for range d.MaxConns {
+			var c *tls.Conn
+			c, err = tls.DialWithDialer(&net.Dialer{Timeout: d.Timeout}, "tcp", d.Addr.String(), d.TLSConfig)
+			if err != nil {
+				break
+			}
+			d.conns <- c
+		}
+	})
+
+	if err != nil {
+		return
+	}
+
+	c := <-d.conns
+
+	return c, nil
+}
+
+func (d *TLSDialer) put(conn net.Conn) {
+	d.conns <- conn
+}
+
 // HTTPDialer is a custom dialer for creating HTTP connections.
 // It allows sending HTTP requests with a specified endpoint, user agent, and transport configuration.
 type HTTPDialer struct {