[client,signal,management] Add browser client support (#4415)

client/grpc/dialer_generic.go

@@ -0,0 +1,44 @@
+//go:build !js
+
+package grpc
+
+import (
+	"context"
+	"fmt"
+	"net"
+	"os/user"
+	"runtime"
+
+	"google.golang.org/grpc/codes"
+	"google.golang.org/grpc/status"
+
+	log "github.com/sirupsen/logrus"
+	"google.golang.org/grpc"
+
+	nbnet "github.com/netbirdio/netbird/client/net"
+)
+
+func WithCustomDialer(tlsEnabled bool) grpc.DialOption {
+	return grpc.WithContextDialer(func(ctx context.Context, addr string) (net.Conn, error) {
+		if runtime.GOOS == "linux" {
+			currentUser, err := user.Current()
+			if err != nil {
+				return nil, status.Errorf(codes.FailedPrecondition, "failed to get current user: %v", err)
+			}
+
+			// the custom dialer requires root permissions which are not required for use cases run as non-root
+			if currentUser.Uid != "0" {
+				log.Debug("Not running as root, using standard dialer")
+				dialer := &net.Dialer{}
+				return dialer.DialContext(ctx, "tcp", addr)
+			}
+		}
+
+		conn, err := nbnet.NewDialer().DialContext(ctx, "tcp", addr)
+		if err != nil {
+			log.Errorf("Failed to dial: %s", err)
+			return nil, fmt.Errorf("nbnet.NewDialer().DialContext: %w", err)
+		}
+		return conn, nil
+	})
+}