zone.lisp: Support for DKIM key records.

Reads the key data from a PEM file.  Splits stuff into multiple lines in
a vaguely sensible way.

diff --git a/zone.lisp b/zone.lisp
index 909f755..762c6e2 100644 (file)
--- a/zone.lisp
+++ b/zone.lisp
@@ -622,6 +622,48 @@
   ":txt TEXT"
   (rec :data data))
 
+(defzoneparse :dkim (name data rec)
+  ":dkim (KEYFILE {:TAG VALUE}*)"
+  (destructuring-bind (file &rest plist) (listify data)
+    (let ((things nil) (out nil))
+      (labels ((flush ()
+                (when out
+                  (push (get-output-stream-string out) things)
+                  (setf out nil)))
+              (emit (text)
+                (let ((len (length text)))
+                  (when (and out (> (+ (file-position out)
+                                       (length text))
+                                    64))
+                    (flush))
+                  (when (plusp len)
+                    (cond ((< len 64)
+                           (unless out (setf out (make-string-output-stream)))
+                           (write-string text out))
+                          (t
+                           (do ((i 0 j)
+                                (j 64 (+ j 64)))
+                               ((>= i len))
+                             (push (subseq text i (min j len)) things))))))))
+       (do ((p plist (cddr p)))
+           ((endp p))
+         (emit (format nil "~(~A~)=~A;" (car p) (cadr p))))
+       (emit (with-output-to-string (out)
+               (write-string "p=" out)
+               (when file
+                 (with-open-file (in file :direction :input)
+                   (loop
+                     (when (string= (read-line in)
+                                    "-----BEGIN PUBLIC KEY-----")
+                       (return)))
+                   (loop
+                     (let ((line (read-line in)))
+                       (if (string= line "-----END PUBLIC KEY-----")
+                           (return)
+                           (write-string line out)))))))))
+      (rec :type :txt
+          :data (nreverse things)))))
+
 (defzoneparse :mx (name data rec :zname zname)
   ":mx ((HOST :prio INT :ip IPADDR)*)"
   (dolist (mx (listify data))