zone.lisp: Support for SSHFP records.

Fingerprints can be supplied explicitly or read from files in the
format written by ssh-keygen(1).

diff --git a/zone.lisp b/zone.lisp
index 762c6e26a5517a44024766ce7f1fabce62815e2b..8d35c0976dff20284c3f8c86efbccc042e1b2be6 100644 (file)
--- a/zone.lisp
+++ b/zone.lisp
@@ -664,6 +664,45 @@ (defzoneparse :dkim (name data rec)
       (rec :type :txt
           :data (nreverse things)))))
 
+(eval-when (:load-toplevel :execute)
+  (dolist (item '((sshfp-algorithm rsa 1)
+                 (sshfp-algorithm dsa 2)
+                 (sshfp-algorithm ecdsa 3)
+                 (sshfp-type sha-1 1)
+                 (sshfp-type sha-256 2)))
+    (destructuring-bind (prop sym val) item
+      (setf (get sym prop) val)
+      (export sym))))
+
+(defzoneparse :sshfp (name data rec)
+  ":sshfp { FILENAME | ((FPR :alg ALG :type HASH)*) }"
+  (if (stringp data)
+      (with-open-file (in data)
+       (loop (let ((line (read-line in nil)))
+               (unless line (return))
+               (let ((words (str-split-words line)))
+                 (pop words)
+                 (when (string= (car words) "IN") (pop words))
+                 (unless (and (string= (car words) "SSHFP")
+                              (= (length words) 4))
+                   (error "Invalid SSHFP record."))
+                 (pop words)
+                 (destructuring-bind (alg type fpr) words
+                   (rec :data (list (parse-integer alg)
+                                    (parse-integer type)
+                                    fpr)))))))
+      (flet ((lookup (what prop)
+              (etypecase what
+                (fixnum what)
+                (symbol (or (get what prop)
+                            (error "~S is not a known ~A" what prop))))))
+       (dolist (item (listify data)
+                (destructuring-bind (fpr &key (alg 'rsa) (type 'sha-1))
+                    (listify item)
+                  (rec :data (list (lookup alg 'sshfp-algorithm)
+                                   (lookup type 'sshfp-type)
+                                   fpr))))))))
+
 (defzoneparse :mx (name data rec :zname zname)
   ":mx ((HOST :prio INT :ip IPADDR)*)"
   (dolist (mx (listify data))
@@ -937,6 +976,8 @@ (defgeneric bind-record-format-args (type data)
   (:method ((type (eql :srv)) data)
     (destructuring-bind (prio weight port host) data
       (list "~2D ~5D ~5D ~A" prio weight port (bind-hostname host))))
+  (:method ((type (eql :sshfp)) data)
+    (cons "~2D ~2D ~A" data))
   (:method ((type (eql :txt)) data)
     (cons "~#[\"\"~;~S~:;(~@{~%~8T~S~} )~]"
          (mapcar #'stringify (listify data)))))