dns-suite.js/packer/type.caa.js

70 lines
2.3 KiB
JavaScript

(function (exports) {
'use strict';
// RFC 6844
// Explanation: https://tools.ietf.org/html/rfc6844#section-3
// Binary Format: https://tools.ietf.org/html/rfc6844#section-5
// Real-world Usage: https://support.dnsimple.com/articles/caa-record/
// A Certification Authority Authorization (CAA) record is used to specify which
// certificate authorities (CAs) are allowed to issue certificates for a domain.
// Value Meaning/Use
//
// Flag An unsigned integer between 0-255.
// It is currently used to represent the critical flag, that has a
// specific meaning per RFC 6844
// Tag An ASCII string that represents the identifier of the property
// represented by the record.
// Value The value associated with the tag.
// The RFC currently defines 3 available tags:
//
// - issue: explicity authorizes a single certificate authority to issue a
// certificate (any type) for the hostname.
// - issuewild: explicity authorizes a single certificate authority to issue a
// wildcard certificate (and only wildcard) for the hostname.
// - iodef: specifies an URL to which a certificate authority may report
// policy violations.
exports.DNS_PACKER_TYPE_CAA = function (ab, dv, total, record) {
if ('number' !== typeof record.flag || isNaN(record.flag) || record.flag < 0 || record.flag > 255) {
console.log(record);
throw new Error("bad CAA flag:", record.flag);
}
if ('string' !== typeof record.tag || !record.tag || record.tag.length > 255) {
throw new Error("bad CAA tag:", record.tag);
}
if ('string' !== typeof record.value || !record.value) {
throw new Error("bad CAA value:", record.value);
}
// RDLEN = flag (1 byte) + taglen (1 byte) + tagstr (taglen bytes) + valuestr (valuelen bytes)
dv.setUint16(total, 1 + 1 + record.tag.length + record.value.length, false);
total += 2;
// FLAG
dv.setUint8(total, record.flag, false);
total += 1;
// TAG LENGTH
dv.setUint8(total, record.tag.length, false);
total += 1;
// TAG
record.tag.split('').forEach(function (ch) {
dv.setUint8(total, ch.charCodeAt(0), false);
total += 1;
});
// VALUE
record.value.split('').forEach(function (ch) {
dv.setUint8(total, ch.charCodeAt(0), false);
total += 1;
});
return total;
};
}('undefined' !== typeof window ? window : exports));