feat: HTTP connect proxy support

fix: Add SNI for TLS connections if one is not set

Signed-off-by: amir-khassaia <[email protected]>

http_proxy.go

@@ -0,0 +1,85 @@
+package mqtt
+
+import (
+	"bufio"
+	"fmt"
+	"net"
+	"net/http"
+	"net/url"
+
+	"golang.org/x/net/proxy"
+)
+
+// httpProxy is a HTTP/HTTPS connect capable proxy.
+type httpProxy struct {
+	host     string
+	haveAuth bool
+	username string
+	password string
+	forward  proxy.Dialer
+}
+
+func (s httpProxy) String() string {
+	return fmt.Sprintf("HTTP proxy dialer for %s", s.host)
+}
+
+func newHTTPProxy(uri *url.URL, forward proxy.Dialer) (proxy.Dialer, error) {
+	s := new(httpProxy)
+	s.host = uri.Host
+	s.forward = forward
+	if uri.User != nil {
+		s.haveAuth = true
+		s.username = uri.User.Username()
+		s.password, _ = uri.User.Password()
+	}
+
+	return s, nil
+}
+
+func (s *httpProxy) Dial(_, addr string) (net.Conn, error) {
+	reqURL := url.URL{
+		Scheme: "https",
+		Host:   addr,
+	}
+
+	req, err := http.NewRequest("CONNECT", reqURL.String(), nil)
+	if err != nil {
+		return nil, err
+	}
+	req.Close = false
+	if s.haveAuth {
+		req.SetBasicAuth(s.username, s.password)
+	}
+	req.Header.Set("User-Agent", "paho.mqtt")
+
+	// Dial and create the client connection.
+	c, err := s.forward.Dial("tcp", s.host)
+	if err != nil {
+		return nil, err
+	}
+
+	err = req.Write(c)
+	if err != nil {
+		_ = c.Close()
+		return nil, err
+	}
+
+	resp, err := http.ReadResponse(bufio.NewReader(c), req)
+	if err != nil {
+		_ = c.Close()
+		return nil, err
+	}
+	_ = resp.Body.Close()
+	if resp.StatusCode != 200 {
+		_ = c.Close()
+		err = fmt.Errorf("connect server using proxy error, StatusCode [%d]", resp.StatusCode)
+		return nil, err
+	}
+
+	return c, nil
+}
+
+func init() {
+	proxy.RegisterDialerType("http", newHTTPProxy)
+	proxy.RegisterDialerType("https", newHTTPProxy)
+}

netconn.go

@@ -77,7 +77,7 @@ func openConnection(uri *url.URL, tlsc *tls.Config, timeout time.Duration, heade
 			return nil, err
 		}
 
-		tlsConn := tls.Client(conn, tlsc)
+		tlsConn := tls.Client(conn, tlsConfigWithSni(uri, tlsc))
 
 		err = tlsConn.Handshake()
 		if err != nil {
@@ -89,3 +89,14 @@ func openConnection(uri *url.URL, tlsc *tls.Config, timeout time.Duration, heade
 	}
 	return nil, errors.New("unknown protocol")
 }
+
+func tlsConfigWithSni(uri *url.URL, conf *tls.Config) *tls.Config {
+	tlsConfig := conf
+	if tlsConfig.ServerName == "" {
+		// Ensure SNI is set appropriately - make a copy to avoid polluting argument or default.
+		c := tlsConfig.Clone()
+		c.ServerName = uri.Hostname()
+		tlsConfig = c
+	}
+	return tlsConfig
+}