(car slot))
(cdr slot)))
slots))
- (slot-desc (mapcar #'car slots)))
+ (slot-desc (mapcar #'(lambda (slot)
+ (let ((name (car slot)))
+ `(,name :initarg ,(intern (symbol-name name) (find-package :keyword))))) slots)))
`(progn
(defclass ,name (resource-record) ,slot-desc)
(setf *rr-coding-types* (cons '(,name (,class ,type) ,format)
(decoded (append (list label) (decode-label))))
(push (cons orig-off decoded) (slot-value buf 'prev-names))
decoded))))
- ((3) (let* ((offset (+ (* 256 (ldb (byte 0 6) len))
+ ((3) (let* ((offset (+ (* 256 (ldb (byte 6 0) len))
(decode-uint-8 buf)))
(prev (assoc offset (dns-decode-state-prev-names buf))))
(unless prev
(concatenate 'string buf "." label)
label)))))
+;;; Basic communication
+
+(define-condition name-server-timeout (dns-error)
+ ((server :initarg :server)))
+
+(defun dns-do-request (server packet)
+ (declare (type address server)
+ (type dns-packet packet))
+ (with-connection (sk server)
+ (socket-send sk (dns-encode packet))
+ (loop
+ (let ((resp (dns-decode (socket-recv sk))))
+ (when (= (dns-packet-txid resp)
+ (dns-packet-txid packet))
+ (return resp))))))
+
+(defun dns-std-request (queries &key (txid (random 65536)) (recurse t))
+ (let ((qlist (map 'list #'(lambda (o)
+ (let ((name (first o))
+ (type (second o)))
+ (make-instance 'resource-query
+ :name (etypecase name
+ (string (parse-domain-name name))
+ (list name))
+ :type type)))
+ queries)))
+ (make-dns-packet :txid txid
+ :recurse recurse
+ :queries qlist)))
+
+;;; RR caching
+
+(defstruct domain-cache-entry
+ (expire nil :type (or number null))
+ (records '() :type list))
+
+(defun domain-cache-key (name type)
+ (list name (etypecase type
+ (symbol type)
+ (resource-record (class-name (class-of type))))))
+
+(defun domain-cache-key-rr (record)
+ (declare (type resource-record record))
+ (list (slot-value record 'name) (class-name (class-of record))))
+
+(defun domain-cache-get-entry (cache name type &optional create)
+ (let* ((key (domain-cache-key name type))
+ (cur (gethash key cache)))
+ (when (and cur (or (eq create :clear)
+ (let ((expire (domain-cache-entry-expire cur)))
+ (and expire
+ (> (/ (get-internal-real-time) internal-time-units-per-second)
+ expire)))))
+ (remhash key cache)
+ (setf cur nil))
+ (cond (cur cur)
+ (create
+ (setf (gethash key cache) (make-domain-cache-entry))))))
+
+(defun domain-cache-put (cache record)
+ (with-slots (name ttl) record
+ (let ((entry (domain-cache-get-entry cache name record t)))
+ (push record (domain-cache-entry-records entry)))))
+
+(defun dns-cache-records (cache records)
+ (loop (unless records (return))
+ (let* ((key (domain-cache-key-rr (car records)))
+ (matching (remove key records :test-not 'equal :key #'domain-cache-key-rr))
+ (ttl (block no-expire
+ (+ (/ (get-internal-real-time) internal-time-units-per-second)
+ (apply 'min (mapcar #'(lambda (rr)
+ (with-slots (ttl) rr
+ (if ttl ttl (return-from no-expire nil))))
+ matching)))))
+ (entry (make-domain-cache-entry :expire ttl :records matching)))
+ (setf (gethash key cache) entry
+ records (set-difference records matching)))))
+
+(defun dns-cache-response (cache packet)
+ (let ((records (append (dns-packet-answers packet)
+ (dns-packet-authority packet)
+ (dns-packet-additional packet))))
+ (flet ((on-root (rr)
+ (equal (slot-value rr 'name) '())))
+ (when (some #'on-root records)
+ (warn "DNS packet purports to contain RRs on the root zone.")
+ (setf records (delete-if #'on-root records))))
+ (when (dns-packet-authoritative packet)
+ (dolist (rq (dns-packet-queries packet))
+ (with-slots (name type) rq
+ (unless (equal name '())
+ (let ((key (domain-cache-key name type)))
+ (unless (find key records :test 'equal :key #'domain-cache-key-rr)
+ (let ((entry (domain-cache-get-entry cache name type :clear)))
+ (setf (domain-cache-entry-expire entry)
+ (+ (/ (get-internal-real-time) internal-time-units-per-second)
+ 60))))))))) ; XXX: Or something. It needs
+ ; to last for the query in
+ ; progress, at least. One
+ ; should probably look at an
+ ; SOA RR, if there is one.
+ (dns-cache-records cache records)))
+
+(defun make-domain-cache ()
+ (let ((table (make-hash-table :test 'equal)))
+ (dolist (server (labels ((ipv4 (address)
+ (make-instance 'ipv4-host-address :host-string address)))
+ `(("a.root-servers.net" ,(ipv4 "198.41.0.4"))
+ ("b.root-servers.net" ,(ipv4 "192.228.79.201"))
+ ("c.root-servers.net" ,(ipv4 "192.33.4.12"))
+ ("d.root-servers.net" ,(ipv4 "128.8.10.90"))
+ ("e.root-servers.net" ,(ipv4 "192.203.230.10"))
+ ("f.root-servers.net" ,(ipv4 "192.5.5.241"))
+ ("g.root-servers.net" ,(ipv4 "192.112.36.4"))
+ ("h.root-servers.net" ,(ipv4 "128.63.2.53"))
+ ("i.root-servers.net" ,(ipv4 "192.36.148.17"))
+ ("j.root-servers.net" ,(ipv4 "192.58.128.30"))
+ ("k.root-servers.net" ,(ipv4 "193.0.14.129"))
+ ("l.root-servers.net" ,(ipv4 "199.7.83.42"))
+ ("m.root-servers.net" ,(ipv4 "202.12.27.33")))))
+ (let ((parsed (parse-domain-name (first server))))
+ (domain-cache-put table (make-instance 'ns-record :name '() :ttl nil :ns-name parsed))
+ ;; Ensure that the cache is initialized at least with empty
+ ;; lists, so that the resolver doesn't try to resolve the root
+ ;; servers.
+ (domain-cache-get-entry table parsed 'a-record t)
+ (domain-cache-get-entry table parsed 'aaaa-record t)
+
+ (dolist (address (cdr server))
+ (domain-cache-put table (etypecase address
+ (ipv4-host-address (make-instance 'a-record :name parsed :ttl nil :address address)))))))
+ table))
+
+;;; Resolver
+
+(defstruct resolver-config
+ (cache (make-domain-cache))
+ (default-domains '() :type list)
+ (help-servers '() :type list))
+
+(defun initialize-default-resolver ()
+ #+unix (with-open-file (s #p"/etc/resolv.conf" :if-does-not-exist nil)
+ (when s
+ (let ((cfg (make-resolver-config)))
+ (labels ((whitespace-p (char)
+ (declare (type character char))
+ (or (char= char #\space)
+ (char= char #\tab)))
+ (split-line (line)
+ (let ((l '())
+ (p 0))
+ (loop (let* ((p1 (or (position-if-not #'whitespace-p line :start p)
+ (return l)))
+ (p2 (position-if #'whitespace-p line :start p1)))
+ (if p2
+ (setf l (append l (list (subseq line p1 p2)))
+ p p2)
+ (progn (setf l (append l (list (subseq line p1 p2))))
+ (return l))))))))
+ (let ((domain nil)
+ (search '()))
+ (loop (let ((line (read-line s nil nil)))
+ (unless line (return))
+ (let ((line (split-line line)))
+ (when line
+ (cond ((equal (car line) "nameserver")
+ (push (make-instance 'ipv4-address :host-string (second line))
+ (resolver-config-help-servers cfg)))
+ ((equal (car line) "search")
+ (setf search (append search (cdr line))))
+ ((equal (car line) "domain")
+ (setf domain (second line))))))))
+ (setf (resolver-config-default-domains cfg)
+ (or search (and domain (list domain)))))
+ cfg))))
+ #-unix nil)
+
+(defvar *dns-resolver-config* (initialize-default-resolver))
+
+(defgeneric dns-server-address-for-record (record))
+
;;; Misc.
(defmethod print-object ((q resource-query) stream)
Dolda2000 GitWeb / lisp-utils.git / blobdiff