X-Git-Url: http://cgit.sxemacs.org/?a=blobdiff_plain;f=lisp%2Fdns.el;h=f23e87a6bcd4790804e711603bc3360fb46ea6ca;hb=3f8329904865e576f8046a203db287b018094759;hp=1c5b4b6f0822e63dba71340f8aea76b175f684c8;hpb=000d44b99765442c07e930cfac062859b88e1bb4;p=gnus

diff --git a/lisp/dns.el b/lisp/dns.el
index 1c5b4b6f0..f23e87a6b 100644
--- a/lisp/dns.el
+++ b/lisp/dns.el
@@ -1,5 +1,5 @@
 ;;; dns.el --- Domain Name Service lookups
-;; Copyright (C) 2002 Free Software Foundation, Inc.
+;; Copyright (C) 2002, 2003 Free Software Foundation, Inc.
 
 ;; Author: Lars Magne Ingebrigtsen <larsi@gnus.org>
 ;; Keywords: network
@@ -25,11 +25,17 @@
 
 ;;; Code:
 
+(eval-when-compile (require 'cl))
+
 (require 'mm-util)
 
 (defvar dns-timeout 5
   "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.")
+
 ;;; Internal code:
 
 (defvar dns-query-types
@@ -121,11 +127,14 @@
 				  (progn (forward-char length) (point)))
 		name))))
     (if (stringp ended)
-	(concat (mapconcat 'identity (nreverse name) ".") "." ended)
+	(if (null name)
+	    ended
+	  (concat (mapconcat 'identity (nreverse name) ".") "." ended))
       (mapconcat 'identity (nreverse name) "."))))
 
-(defun dns-write (spec)
-  "Write a DNS packet according to SPEC."
+(defun dns-write (spec &optional tcp-p)
+  "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
     (dns-write-bytes (dns-get 'id spec) 2)
     (dns-write-bytes
@@ -170,6 +179,9 @@
       (dns-write-bytes (dns-get 'ttl resource) 4)
       (dns-write-bytes (length (dns-get 'data resource)) 2)
       (insert (dns-get 'data resource))))
+    (when tcp-p
+      (goto-char (point-min))
+      (dns-write-bytes (buffer-size) 2))
     (buffer-string)))
 
 (defun dns-read (packet)
@@ -254,43 +266,91 @@
 	      (mapconcat 'number-to-string (nreverse bytes) ".")))
 	   ((eq type 'NS)
 	    (dns-read-string-name string buffer))
+	   ((eq type 'CNAME)
+	    (dns-read-string-name string buffer))
 	   (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)))))
+
 ;;; Interface functions.
 
-(defun query-dns (name &optional type)
-  "Query a DNS server for NAME of TYPE."
+(autoload 'gnus-xmacs-open-network-stream "gnus-xmas" nil nil 'macro)
+
+(defmacro dns-make-network-process (server)
+  (if (featurep 'xemacs)
+      `(let ((coding-system-for-read 'binary)
+	     (coding-system-for-write 'binary))
+	 (gnus-xmas-open-network-stream "dns" (current-buffer)
+					,server "domain" 'udp))
+    `(let ((server ,server)
+	   (coding-system-for-read 'binary)
+	   (coding-system-for-write 'binary))
+       (if (fboundp 'make-network-process)
+	   (make-network-process
+	    :name "dns"
+	    :coding 'binary
+	    :buffer (current-buffer)
+	    :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)
+  "Query a DNS server for NAME of TYPE.
+If FULLP, return the entire record returned."
   (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 ((coding-system-for-read 'binary) 
-	  (coding-system-for-write 'binary))
-      (let ((process
-	     (make-network-process
-	      :name "dns"
-	      :coding 'binary
-	      :buffer (current-buffer)
-	      :host "ns2.netfonds.no"
-	      :service "domain"
-	      :type 'datagram))
-	    (step 100)
-	    (times (* dns-timeout 1000)))
+    (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 4)
+	 (dns-write `((id ,id)
 		      (opcode query)
 		      (queries ((,name (type ,type))))
-		      (recursion-desired-p t))))
+		      (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))
-	(let ((answer (car (dns-get 'answers (dns-read (buffer-string))))))
-	  (when (eq type (dns-get 'type answer))
-	    (dns-get 'data answer)))))))
-    
+	(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))))))))))
+
 (provide 'dns)
 
 ;;; dns.el ends here