Add race dialer

relay/client/client.go

@@ -10,7 +10,9 @@ import (
 	log "github.com/sirupsen/logrus"
 
 	auth "github.com/netbirdio/netbird/relay/auth/hmac"
+	"github.com/netbirdio/netbird/relay/client/dialer"
 	"github.com/netbirdio/netbird/relay/client/dialer/quic"
+	"github.com/netbirdio/netbird/relay/client/dialer/ws"
 	"github.com/netbirdio/netbird/relay/healthcheck"
 	"github.com/netbirdio/netbird/relay/messages"
 )
@@ -259,7 +261,7 @@ func (c *Client) Close() error {
 }
 
 func (c *Client) connect() error {
-	conn, err := quic.Dial(c.connectionURL)
+	conn, err := dialer.RaceDial(c.connectionURL, quic.Dial, ws.Dial)
 	if err != nil {
 		return err
 	}

relay/client/dialer/race_dialer.go

@@ -0,0 +1,63 @@
+package dialer
+
+import (
+	"context"
+	"errors"
+	"net"
+	"time"
+
+	log "github.com/sirupsen/logrus"
+)
+
+type DialFn func(ctx context.Context, address string) (net.Conn, error)
+
+type dialResult struct {
+	Conn net.Conn
+	Err  error
+}
+
+func RaceDial(serverURL string, DialFns ...DialFn) (net.Conn, error) {
+	connChan := make(chan dialResult, len(DialFns))
+	winnerConn := make(chan net.Conn, 1)
+	abortCtx, abort := context.WithCancel(context.Background())
+	defer abort()
+
+	for _, dfn := range DialFns {
+		go func() {
+			ctx, cancel := context.WithTimeout(abortCtx, 30*time.Second)
+			defer cancel()
+
+			conn, err := dfn(ctx, serverURL)
+			if err != nil {
+				log.Errorf("failed to dial: %s", err)
+			}
+
+			connChan <- dialResult{Conn: conn, Err: err}
+		}()
+	}
+
+	go func() {
+		var hasWinner bool
+		for i := 0; i < len(DialFns); i++ {
+			dr := <-connChan
+			if dr.Err != nil {
+				continue
+			}
+
+			if hasWinner {
+				_ = dr.Conn.Close()
+				continue
+			}
+
+			hasWinner = true
+			winnerConn <- dr.Conn
+		}
+		close(winnerConn)
+	}()
+
+	conn, ok := <-winnerConn
+	if !ok {
+		return nil, errors.New("failed to dial to Relay server")
+	}
+	return conn, nil
+}