;;; dns.el --- Domain Name Service lookups
-;; Copyright (C) 2002 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
;; 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,
;; 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:
;;; Code:
+(eval-when-compile (require 'cl))
+
(require 'mm-util)
(defvar dns-timeout 5
(MR 9)
(NULL 10)
(WKS 11)
- (PRT 12)
+ (PTR 12)
(HINFO 13)
(MINFO 14)
(MX 15)
(TXT 16)
+ (AAAA 28) ; RFC3596
+ (SRV 33) ; RFC2782
(AXFR 252)
(MAILB 253)
(MAILA 254)
(push (list slot qs) spec)))
(nreverse spec))))
+(defun dns-read-int32 ()
+ ;; Full 32 bit Integers can't be handled by Emacs. If we use
+ ;; floats, it works.
+ (format "%.0f" (+ (* (dns-read-bytes 1) 16777216.0)
+ (dns-read-bytes 3))))
+
(defun dns-read-type (string type)
(let ((buffer (current-buffer))
(point (point)))
(dotimes (i 4)
(push (dns-read-bytes 1) bytes))
(mapconcat 'number-to-string (nreverse bytes) ".")))
- ((eq type 'NS)
- (dns-read-string-name string buffer))
- ((eq type 'CNAME)
+ ((eq type 'AAAA)
+ (let (hextets)
+ (dotimes (i 8)
+ (push (dns-read-bytes 2) hextets))
+ (mapconcat (lambda (n) (format "%x" n)) (nreverse hextets) ":")))
+ ((eq type 'SOA)
+ (list (list 'mname (dns-read-name buffer))
+ (list 'rname (dns-read-name buffer))
+ (list 'serial (dns-read-int32))
+ (list 'refresh (dns-read-int32))
+ (list 'retry (dns-read-int32))
+ (list 'expire (dns-read-int32))
+ (list 'minimum (dns-read-int32))))
+ ((eq type 'SRV)
+ (list (list 'priority (dns-read-bytes 2))
+ (list 'weight (dns-read-bytes 2))
+ (list 'port (dns-read-bytes 2))
+ (list 'target (dns-read-name buffer))))
+ ((eq type 'MX)
+ (cons (dns-read-bytes 2) (dns-read-name buffer)))
+ ((or (eq type 'CNAME) (eq type 'NS) (eq type 'PTR))
(dns-read-string-name string buffer))
(t string)))
(goto-char point))))
(push (match-string 1) dns-servers))
(setq dns-servers (nreverse dns-servers)))))
-;;; Interface functions.
+(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)
`(let ((coding-system-for-read 'binary)
(coding-system-for-write 'binary))
- (open-network-stream "dns" (current-buffer) ,server "domain" 'udp))
+ (open-network-stream "dns" (current-buffer)
+ ,server "domain" 'udp))
`(let ((server ,server)
(coding-system-for-read 'binary)
(coding-system-for-write 'binary))
:host server
:service "domain"
:type 'datagram)
+ ;; Older versions of Emacs doesn't have
+ ;; `make-network-process', so we fall back on opening a TCP
+ ;; 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)
- (unless dns-servers
- (error "No DNS server configuration found")))
- (mm-with-unibyte-buffer
- (let ((process (dns-make-network-process (car dns-servers)))
- (tcp-p (and (not (fboundp 'make-network-process))
- (not (featurep 'xemacs))))
- (step 100)
- (times (* dns-timeout 1000))
- (id (random 65000)))
- (process-send-string
- process
- (dns-write `((id ,id)
- (opcode query)
- (queries ((,name (type ,type))))
- (recursion-desired-p t))
- tcp-p))
- (while (and (zerop (buffer-size))
- (> times 0))
- (accept-process-output process 0 step)
- (decf times step))
- (ignore-errors
- (delete-process process))
- (when tcp-p
- (goto-char (point-min))
- (delete-region (point) (+ (point) 2)))
- (unless (zerop (buffer-size))
- (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)))))))))
+ (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
+ (let ((process (condition-case ()
+ (dns-make-network-process (car dns-servers))
+ (error
+ (message "dns: Got an error while trying to talk to %s"
+ (car dns-servers))
+ nil)))
+ (tcp-p (and (not (fboundp 'make-network-process))
+ (not (featurep 'xemacs))))
+ (step 100)
+ (times (* dns-timeout 1000))
+ (id (random 65000)))
+ (when process
+ (process-send-string
+ process
+ (dns-write `((id ,id)
+ (opcode query)
+ (queries ((,name (type ,type))))
+ (recursion-desired-p t))
+ 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 (and tcp-p
+ (>= (buffer-size) 2))
+ (goto-char (point-min))
+ (delete-region (point) (+ (point) 2)))
+ (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))
+ (if (eq type 'TXT)
+ (dns-get-txt-answer (dns-get 'answers result))
+ (dns-get 'data answer))))))))))))
(provide 'dns)
+;;; arch-tag: d0edd0c4-4cce-4538-ae92-06c3356ee80a
;;; dns.el ends here
projects / gnus / blobdiff