;;; dns.el --- Domain Name Service lookups
-;; Copyright (C) 2002, 2003, 2004, 2005, 2006, 2007, 2008
-;; Free Software Foundation, Inc.
+;; Copyright (C) 2002-2015 Free Software Foundation, Inc.
;; Author: Lars Magne Ingebrigtsen <larsi@gnus.org>
-;; Keywords: network
+;; Keywords: network comm
;; This file is part of GNU Emacs.
"How many seconds to wait when doing DNS queries.")
(defvar dns-servers nil
- "Which DNS servers to query.
-If nil, /etc/resolv.conf will be consulted.")
+ "List of DNS servers to query.
+If nil, /etc/resolv.conf and nslookup will be consulted.")
+
+(defvar dns-servers-valid-for-interfaces nil
+ "The return value of `network-interface-list' when `dns-servers' was set.
+If the set of network interfaces and/or their IP addresses
+change, then presumably the list of DNS servers needs to be
+updated. Set this variable to t to disable the check.")
;;; Internal code:
(defun dns-read-string-name (string buffer)
(with-temp-buffer
- (set-buffer-multibyte nil)
+ (unless (featurep 'xemacs) (set-buffer-multibyte nil))
(insert string)
(goto-char (point-min))
(dns-read-name buffer)))
"Write a DNS packet according to SPEC.
If TCP-P, the first two bytes of the package with be the length field."
(with-temp-buffer
- (set-buffer-multibyte nil)
+ (unless (featurep 'xemacs) (set-buffer-multibyte nil))
(dns-write-bytes (dns-get 'id spec) 2)
(dns-write-bytes
(logior
(lsh (if (dns-get 'truncated-p spec) 1 0) -1)
(lsh (if (dns-get 'recursion-desired-p spec) 1 0) 0)))
(dns-write-bytes
- (cond
+ (cond
((eq (dns-get 'response-code spec) 'no-error) 0)
((eq (dns-get 'response-code spec) 'format-error) 1)
((eq (dns-get 'response-code spec) 'server-failure) 2)
(defun dns-read (packet)
(with-temp-buffer
- (set-buffer-multibyte nil)
+ (unless (featurep 'xemacs) (set-buffer-multibyte nil))
(let ((spec nil)
queries answers authorities additionals)
(insert packet)
(nreverse spec))))
(defun dns-read-int32 ()
- ;; Full 32 bit Integers can't be handled by Emacs. If we use
- ;; floats, it works.
+ ;; Full 32 bit Integers can't be handled by 32-bit Emacsen. If we
+ ;; use floats, it works.
(format "%.0f" (+ (* (dns-read-bytes 1) 16777216.0)
(dns-read-bytes 3))))
(point (point)))
(prog1
(with-temp-buffer
- (set-buffer-multibyte nil)
+ (unless (featurep 'xemacs) (set-buffer-multibyte nil))
(insert string)
(goto-char (point-min))
(cond
(t string)))
(goto-char point))))
-(defun dns-parse-resolv-conf ()
- (when (file-exists-p "/etc/resolv.conf")
- (with-temp-buffer
- (insert-file-contents "/etc/resolv.conf")
- (goto-char (point-min))
- (while (re-search-forward "^nameserver[\t ]+\\([^ \t\n]+\\)" nil t)
- (push (match-string 1) dns-servers))
- (setq dns-servers (nreverse dns-servers)))))
+(declare-function network-interface-list "process.c")
+
+(defun dns-servers-up-to-date-p ()
+ "Return false if we need to recheck the list of DNS servers."
+ (and dns-servers
+ (or (eq dns-servers-valid-for-interfaces t)
+ ;; `network-interface-list' was introduced in Emacs 22.1.
+ (not (fboundp 'network-interface-list))
+ (equal dns-servers-valid-for-interfaces
+ (network-interface-list)))))
+
+(defun dns-set-servers ()
+ "Set `dns-servers' to a list of DNS servers or nil if none are found.
+Parses \"/etc/resolv.conf\" or calls \"nslookup\"."
+ (or (when (file-exists-p "/etc/resolv.conf")
+ (setq dns-servers nil)
+ (with-temp-buffer
+ (insert-file-contents "/etc/resolv.conf")
+ (goto-char (point-min))
+ (while (re-search-forward "^nameserver[\t ]+\\([^ \t\n]+\\)" nil t)
+ (push (match-string 1) dns-servers))
+ (setq dns-servers (nreverse dns-servers))))
+ (when (executable-find "nslookup")
+ (with-temp-buffer
+ (call-process "nslookup" nil t nil "localhost")
+ (goto-char (point-min))
+ (re-search-forward
+ "^Address:[ \t]*\\([0-9]+\\.[0-9]+\\.[0-9]+\\.[0-9]+\\)" nil t)
+ (setq dns-servers (list (match-string 1))))))
+ (when (fboundp 'network-interface-list)
+ (setq dns-servers-valid-for-interfaces (network-interface-list))))
(defun dns-read-txt (string)
(if (> (length string) 1)
(defvar dns-cache (make-vector 4096 0))
-(defun query-dns-cached (name &optional type fullp reversep)
+(defun dns-query-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)))
+ (let ((result (dns-query name type fullp reversep)))
(set (intern key dns-cache) result)
result))))
-(defun query-dns (name &optional type fullp reversep)
+;; The old names `query-dns' and `query-dns-cached' weren't used in Emacs 23
+;; yet, so no alias are provided. --rsteib
+
+(defun dns-query (name &optional type fullp reversep)
"Query a DNS server for NAME of TYPE.
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-up-to-date-p)
+ (dns-set-servers))
(when reversep
(setq name (concat
(if (not dns-servers)
(message "No DNS server configuration found")
(with-temp-buffer
- (set-buffer-multibyte nil)
+ (unless (featurep 'xemacs) (set-buffer-multibyte nil))
(let ((process (condition-case ()
(dns-make-network-process (car dns-servers))
(error
(provide 'dns)
-;; arch-tag: d0edd0c4-4cce-4538-ae92-06c3356ee80a
;;; dns.el ends here
projects / gnus / blobdiff