Relicense "GPLv2 or later" files to "GPLv3 or later".

[gnus] / lisp / dns.el

diff --git a/lisp/dns.el b/lisp/dns.el
index 24bce62..7910261 100644 (file)
--- a/lisp/dns.el
+++ b/lisp/dns.el
@@ -1,5 +1,6 @@
 ;;; dns.el --- Domain Name Service lookups
-;; Copyright (C) 2002, 2003, 2004 Free Software Foundation, Inc.
+
+;; Copyright (C) 2002, 2003, 2004, 2005, 2006, 2007 Free Software Foundation, Inc.
 
 ;; Author: Lars Magne Ingebrigtsen <larsi@gnus.org>
 ;; Keywords: network
@@ -8,7 +9,7 @@
 
 ;; GNU Emacs is free software; you can redistribute it and/or modify
 ;; it under the terms of the GNU General Public License as published by
-;; the Free Software Foundation; either version 2, or (at your option)
+;; the Free Software Foundation; either version 3, or (at your option)
 ;; any later version.
 
 ;; GNU Emacs is distributed in the hope that it will be useful,
@@ -18,8 +19,8 @@
 
 ;; You should have received a copy of the GNU General Public License
 ;; along with GNU Emacs; see the file COPYING.  If not, write to the
-;; Free Software Foundation, Inc., 59 Temple Place - Suite 330,
-;; Boston, MA 02111-1307, USA.
+;; Free Software Foundation, Inc., 51 Franklin Street, Fifth Floor,
+;; Boston, MA 02110-1301, USA.
 
 ;;; Commentary:
 
@@ -306,6 +307,25 @@ If TCP-P, the first two bytes of the package with be the length field."
        (push (match-string 1) dns-servers))
       (setq dns-servers (nreverse dns-servers)))))
 
+(defun dns-read-txt (string)
+  (if (> (length string) 1)
+      (substring string 1)
+    string))
+
+(defun dns-get-txt-answer (answers)
+  (let ((result "")
+       (do-next nil))
+    (dolist (answer answers)
+      (dolist (elem answer)
+       (when (consp elem)
+         (cond
+          ((eq (car elem) 'type)
+           (setq do-next (eq (cadr elem) 'TXT)))
+          ((eq (car elem) 'data)
+           (when do-next
+             (setq result (concat result (dns-read-txt (cadr elem))))))))))
+    result))
+
 ;;; Interface functions.
 (defmacro dns-make-network-process (server)
   (if (featurep 'xemacs)
@@ -329,13 +349,32 @@ If TCP-P, the first two bytes of the package with be the length field."
         ;; 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
@@ -360,20 +399,26 @@ If FULLP, return the entire record returned."
                      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
            (delete-process process))
-         (when tcp-p
+         (when (and tcp-p
+                    (>= (buffer-size) 2))
            (goto-char (point-min))
            (delete-region (point) (+ (point) 2)))
-         (unless (zerop (buffer-size))
+         (when (and (>= (buffer-size) 2)
+                    ;; We had a time-out.
+                    (> times 0))
            (let ((result (dns-read (buffer-string))))
              (if fullp
                  result
                (let ((answer (car (dns-get 'answers result))))
                  (when (eq type (dns-get 'type answer))
-                   (dns-get 'data answer)))))))))))
+                   (if (eq type 'TXT)
+                       (dns-get-txt-answer (dns-get 'answers result))
+                     (dns-get 'data answer))))))))))))
 
 (provide 'dns)