crossdomain.vcl

sub vcl_recv {
    if (req.url == "/crossdomain.xml") {
        error 843 "OK";
    }
    /* ... */
}

sub vcl_error {
    if (obj.status == 843) {
        set obj.status = 200;
        set obj.http.Content-Type = "application/xml; charset=utf-8";
        set obj.http.Cache-Control = "max-age=2592000";
        remove obj.http.Retry-After;
        synthetic {"<?xml version="1.0" encoding="UTF-8"?>
<cross-domain-policy xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance" xsi:noNamespaceSchemaLocation="http://www.adobe.com/xml/schemas/PolicyFile.xsd">
  <site-control permitted-cross-domain-policies="all" />
  <allow-access-from domain="*" to-ports="*" />
  <allow-http-request-headers-from domain="*" headers="*" />
</cross-domain-policy>
        "};
        deliver;
    }
    /* ... */
}