feat(lisp/dns): Introduce enum for DNS types & decode RDATA

Adds some of the most common DNS types in the enum (others TBD), and
starts decoding RDATA for TXT and A.
This commit is contained in:
Vincent Ambo 2020-01-26 20:29:30 +00:00
parent 72abb43577
commit 4c109f66b6

View file

@ -662,6 +662,21 @@
;; 4.1.3. Resource record format
(defbinary dns-rr (:byte-order :big-endian)
(define-enum dns-type 2
(:byte-order :big-endian)
;; http://www.iana.org/assignments/dns-parameters/dns-parameters.xhtml
(A 1)
(NS 2)
(CNAME 5)
(SOA 6)
(PTR 12)
(MX 15)
(TXT 16)
(SRV 33)
(AAAA 28)
(ANY 255)) ;; (typically wants SOA, MX, NS and MX)
(name nil :type (custom :lisp-type qname
:reader #'read-qname
:writer #'write-qname))
@ -669,7 +684,7 @@
;; two octets containing one of the RR type codes. This
;; field specifies the meaning of the data in the RDATA
;; field.
(type 0 :type 16) ; TODO(tazjin): enum?
(type 0 :type dns-type)
;; two octets which specify the class of the data in the
;; RDATA field.
@ -691,7 +706,11 @@
;; according to the TYPE and CLASS of the resource record.
;; For example, the if the TYPE is A and the CLASS is IN,
;; the RDATA field is a 4 octet ARPA Internet address.
(rdata #() :type (simple-array (unsigned-byte 8) (rdlength))))
(rdata #() :type (eval (case type
;; TODO(tazjin): Deal with multiple strings in single RRDATA
((TXT) '(counted-string 1))
((A) '(simple-array (unsigned-byte 8) (4)))
(otherwise `(simple-array (unsigned-byte 8) (,rdlength)))))))
(defbinary dns-message (:byte-order :big-endian)
(header nil :type dns-header)