Mobile Redirect with varnish

sub vcl_recv {
if (req.http.user-agent ~ "iP(hone|od)|android|(?i)^samsung|(?i)android|(?i)android 3") {
error 750 "Moved Temporarily";
}
}

sub vcl_error {
if (obj.status == 750) {
set obj.http.Location = "http://m.website.com" + req.url;
set obj.status = 301;
return(deliver);

}
}