varnish rewrite

sub vcl_recv {

    if (req.http.host ~ "test1.theron.net" && req.url ~ "test1\?url=(.*)://([^/]*)(.*)$" && req.http.host !~ "valid.theron.net") {

     set req.http.host = regsub(req.url, "^(.*)test1\?url=(.*)://([^/]*)(.*)$","\3");

     set req.url = regsub(req.url, "^(.*)test1\?url=(.*)://([^/]*)(.*)$", "\4");

     }

}