MX record lookups not counted according to RFC 7208

[dominics]

RFC 7208 says:

When evaluating the "mx" mechanism, the number of "MX" resource records queried is included in the overall limit of 10 mechanisms/modifiers that cause DNS lookups as described above.

But countRequest() is only called once, when the MX records are looked up (but not for each record returned that causes an A lookup)

PHP-SPF-Check/src/SPFCheck.php

Lines 243 to 248 in d5b0aa4

	$this->DNSRecordGetter->countRequest();
	$mxServers = $this->DNSRecordGetter->resolveMx($domain);
	if (count($mxServers) > 10) {
	return self::RESULT_PERMERROR;
	}
	foreach ($mxServers as $mxServer) {

There is a check that there isn't more than 10 MX records returned, which matches the following sentence in the RFC ("In addition to that limit, the evaluation of each "MX" record MUST NOT result inmquerying more than 10 address records"), but the lookup of an MX record seems to only count for one DNS request in total (as far as countRequest() goes).

An example of a SPF record that is accepted that should not be is something like:

v=spf1 mx include:foo.example.com include:bar.example.com

with nine MX records attached to the same domain (should be over the limit as defined in the RFC, as it causes 11 DNS lookups, but this library will only count 3 - before includes are evaluated further).