* gnus.el (gnus-other-frame-function): New user option.

[gnus] / lisp / dns.el

diff --git a/lisp/dns.el b/lisp/dns.el
index 6586b9a..475909a 100644 (file)
--- a/lisp/dns.el
+++ b/lisp/dns.el
@@ -30,6 +30,10 @@
 (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 +125,14 @@
                                  (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 +177,9 @@
       (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 +264,79 @@
              (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."
+(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))
+    `(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)
+        (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)))
-       (process-send-string
-        process
-        (dns-write `((id 4)
-                     (opcode query)
-                     (queries ((,name (type ,type))))
-                     (recursion-desired-p t))))
-       (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)))))))
-    
+    (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)))))))))
+
 (provide 'dns)
 
 ;;; dns.el ends here