Add SASL authentication to rcirc

* lisp/net/rcirc.el (rcirc-handler-AUTHENTICATE): New function
(bug#48601).
(rcirc-authenticate):
(rcirc-connect): Support sasl.
(rcirc-get-server-password, rcirc-get-server-method): New functions.
(rcirc-authinfo): Document it.

doc/misc/rcirc.texi

@@ -590,6 +590,12 @@ Use this symbol if you need to identify yourself in the Bitlbee channel
 as follows: @code{identify secret}.  The necessary arguments are the
 nickname you want to use this for, and the password to use.
 
+@item sasl
+@cindex sasl authentication
+Use this symbol if you want to use @acronym{SASL} authentication.  The
+necessary arguments are the nickname you want to use this for, and the
+password to use.
+
 @cindex gateway to other IM services
 @cindex instant messaging, other services
 @cindex Jabber

etc/NEWS

@@ -2134,6 +2134,9 @@ summaries will include the failing condition.
 
 ** Miscellaneous
 
++++
+*** rcirc now supports SASL authentication.
+
 +++
 *** 'save-interprogram-paste-before-kill' can now be a number.
 In that case, it's interpreted as a limit on the size of the clipboard

lisp/net/rcirc.el

@@ -245,13 +245,15 @@ The ARGUMENTS for each METHOD symbol are:
   `chanserv': NICK CHANNEL PASSWORD
   `bitlbee': NICK PASSWORD
   `quakenet': ACCOUNT PASSWORD
+  `sasl': NICK PASSWORD
 
 Examples:
  ((\"freenode\" nickserv \"bob\" \"p455w0rd\")
   (\"freenode\" chanserv \"bob\" \"#bobland\" \"passwd99\")
   (\"bitlbee\" bitlbee \"robert\" \"sekrit\")
   (\"dal.net\" nickserv \"bob\" \"sekrit\" \"NickServ@services.dal.net\")
-  (\"quakenet.org\" quakenet \"bobby\" \"sekrit\"))"
+  (\"quakenet.org\" quakenet \"bobby\" \"sekrit\")
+  (\"oftc\" sasl \"bob\" \"hunter2\"))"
   :type '(alist :key-type (regexp :tag "Server")
 		:value-type (choice (list :tag "NickServ"
 					  (const nickserv)
@@ -269,6 +271,10 @@ Examples:
                                     (list :tag "QuakeNet"
                                           (const quakenet)
                                           (string :tag "Account")
+                                          (string :tag "Password"))
+                                    (list :tag "SASL"
+                                          (const sasl)
+                                          (string :tag "Nick")
                                           (string :tag "Password")))))
 
 (defcustom rcirc-auto-authenticate-flag t
@@ -543,6 +549,22 @@ If ARG is non-nil, instead prompt for connection parameters."
 (defvar rcirc-connection-info nil)
 (defvar rcirc-process nil)
 
+(defun rcirc-get-server-method (server)
+  (catch 'method
+    (dolist (i rcirc-authinfo)
+      (let ((server-i (car i))
+	    (method (cadr i)))
+	(when (string-match server-i server)
+          (throw 'method method))))))
+
+(defun rcirc-get-server-password (server)
+  (catch 'pass
+    (dolist (i rcirc-authinfo)
+      (let ((server-i (car i))
+	    (args (cdddr i)))
+	(when (string-match server-i server)
+          (throw 'pass (car args)))))))
+
 ;;;###autoload
 (defun rcirc-connect (server &optional port nick user-name
                              full-name startup-channels password encryption
@@ -559,6 +581,7 @@ If ARG is non-nil, instead prompt for connection parameters."
 	   (user-name (or user-name rcirc-default-user-name))
 	   (full-name (or full-name rcirc-default-full-name))
 	   (startup-channels startup-channels)
+           (use-sasl (eq (rcirc-get-server-method server) 'sasl))
            (process (open-network-stream
                      (or server-alias server) nil server port-number
                      :type (or encryption 'plain))))
@@ -591,6 +614,8 @@ If ARG is non-nil, instead prompt for connection parameters."
       (setq-local rcirc-server-parameters nil)
 
       (add-hook 'auto-save-hook 'rcirc-log-write)
+      (when use-sasl
+        (rcirc-send-string process "CAP REQ sasl"))
 
       ;; identify
       (unless (zerop (length password))
@@ -598,6 +623,10 @@ If ARG is non-nil, instead prompt for connection parameters."
       (rcirc-send-string process (concat "NICK " nick))
       (rcirc-send-string process (concat "USER " user-name
                                          " 0 * :" full-name))
+      ;; Setup sasl, and initiate authentication.
+      (when (and rcirc-auto-authenticate-flag
+                 use-sasl)
+        (rcirc-send-string process "AUTHENTICATE PLAIN"))
 
       ;; setup ping timer if necessary
       (unless rcirc-keepalive-timer
@@ -2923,7 +2952,8 @@ Passwords are stored in `rcirc-authinfo' (which see)."
                  (rcirc-send-privmsg
                   process
                   "&bitlbee"
-                  (concat "IDENTIFY " (car args)))))
+                  (concat "IDENTIFY " (car args))))
+                (sasl nil))
             ;; quakenet authentication doesn't rely on the user's nickname.
             ;; the variable `nick' here represents the Q account name.
             (when (eq method 'quakenet)
@@ -2969,6 +2999,16 @@ Passwords are stored in `rcirc-authinfo' (which see)."
 
 (defun rcirc-handler-CTCP-response (process _target sender message)
   (rcirc-print process sender "CTCP" nil message t))
+
+(defun rcirc-handler-AUTHENTICATE (process _cmd _args _text)
+  (rcirc-send-string
+   process
+   (format "AUTHENTICATE %s"
+           (base64-encode-string
+            ;; use connection user-name
+            (concat "\0" (nth 3 rcirc-connection-info)
+                    "\0" (rcirc-get-server-password rcirc-server))))))
+
 
 (defgroup rcirc-faces nil
   "Faces for rcirc."