;; connection to the DNS server.
(open-network-stream "dns" (current-buffer) server "domain")))))
-(defun query-dns (name &optional type fullp)
+(defvar dns-cache (make-vector 4096 0))
+
+(defun query-dns-cached (name &optional type fullp reversep)
+ (let* ((key (format "%s:%s:%s:%s" name type fullp reversep))
+ (sym (intern-soft key dns-cache)))
+ (if (and sym
+ (boundp sym))
+ (symbol-value sym)
+ (let ((result (query-dns name type fullp reversep)))
+ (set (intern key dns-cache) result)
+ result))))
+
+(defun query-dns (name &optional type fullp reversep)
"Query a DNS server for NAME of TYPE.
-If FULLP, return the entire record returned."
+If FULLP, return the entire record returned.
+If REVERSEP, look up an IP address."
(setq type (or type 'A))
(unless dns-servers
(dns-parse-resolv-conf))
+ (when reversep
+ (setq name (concat
+ (mapconcat 'identity (nreverse (split-string name "\\.")) ".")
+ ".in-addr.arpa")
+ type 'PTR))
+
(if (not dns-servers)
(message "No DNS server configuration found")
(mm-with-unibyte-buffer
tcp-p))
(while (and (zerop (buffer-size))
(> times 0))
+ (sit-for (/ step 1000.0))
(accept-process-output process 0 step)
(decf times step))
(ignore-errors