1 ;;; proto-stream.el --- negotiating TLS, STARTTLS and other connections
2 ;; Copyright (C) 2010 Free Software Foundation, Inc.
4 ;; Author: Lars Magne Ingebrigtsen <larsi@gnus.org>
7 ;; This file is part of GNU Emacs.
9 ;; GNU Emacs is free software; you can redistribute it and/or modify
10 ;; it under the terms of the GNU General Public License as published by
11 ;; the Free Software Foundation; either version 3, or (at your option)
14 ;; GNU Emacs is distributed in the hope that it will be useful,
15 ;; but WITHOUT ANY WARRANTY; without even the implied warranty of
16 ;; MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
17 ;; GNU General Public License for more details.
19 ;; You should have received a copy of the GNU General Public License
20 ;; along with GNU Emacs; see the file COPYING. If not, write to the
21 ;; Free Software Foundation, Inc., 51 Franklin Street, Fifth Floor,
22 ;; Boston, MA 02110-1301, USA.
26 ;; This library is meant to provide the glue between modules that want
27 ;; to establish a network connection to a server for protocols such as
28 ;; IMAP, NNTP, SMTP and POP3.
30 ;; The main problem is that there's more than a couple of interfaces
31 ;; towards doing this. You have normal, plain connections, which are
32 ;; no trouble at all, but you also have TLS/SSL connections, and you
33 ;; have STARTTLS. Negotiating this for each protocol can be rather
34 ;; tedious, so this library provides a single entry point, and hides
35 ;; much of the ugliness.
40 ;; "*nnimap*" buffer address port
42 ;; :capability-command "1 CAPABILITY\r\n"
44 ;; (lambda (capabilities)
45 ;; (if (not (string-match "STARTTLS" capabilities))
55 (require 'format-spec)
57 (declare-function gnutls-negotiate "gnutls"
58 (proc type &optional priority-string trustfiles keyfiles))
61 (defun open-proto-stream (name buffer host service &rest parameters)
62 "Open a network stream to HOST.
63 The first four parameters have the same meaning as in
64 `open-network-stream'. The function returns a list where the
65 first element is the stream, the second element is the greeting
66 the server replied with after connecting, and the third element
67 is a string representing the capabilities of the server (if any).
69 The PARAMETERS is a keyword list that can have the following
72 :type -- either `network', `tls', `shell' or `starttls'. If
73 omitted, the default is `network'.
75 :end-of-command -- a regexp saying what the end of a command is.
76 This defaults to \"\\n\".
78 :capability-command -- a string representing the command used to
79 query server for capabilities. For instance, for IMAP this is
80 \"1 CAPABILITY\\r\\n\".
82 :starttls-function -- a function that takes one parameter, which
83 is the response to the capaibility command. It should return nil
84 if it turns out that the server doesn't support STARTTLS, or the
85 command to switch on STARTTLS otherwise."
86 (let ((type (or (cadr (memq :type parameters)) 'network)))
87 (when (and (eq type 'starttls)
88 (fboundp 'open-gnutls-stream))
92 (destructuring-bind (stream greeting capabilities)
93 (funcall (intern (format "proto-stream-open-%s" type) obarray)
94 name buffer host service parameters)
96 (memq (process-status stream)
99 greeting capabilities))))
101 (defun proto-stream-open-network (name buffer host service parameters)
102 (let* ((start (with-current-buffer buffer (point)))
103 (stream (open-network-stream name buffer host service))
104 (capability-command (cadr (memq :capability-command parameters)))
105 (greeting (proto-stream-get-response
106 stream start (proto-stream-eoc parameters))))
107 (if (not capability-command)
108 (list stream greeting nil)
110 (proto-stream-capabilities stream capability-command
111 (proto-stream-eoc parameters)))
113 (funcall (cadr (memq :starttls-function parameters))
116 ((not starttls-command)
117 ;; If this server doesn't support STARTTLS, but we have
118 ;; requested it explicitly, then close the connection and
120 (if (eq (cadr (memq :type parameters)) 'starttls)
122 (delete-process stream)
124 ;; Otherwise, just return this plain network connection.
125 (list stream greeting capabilities)))
126 ((fboundp 'open-gnutls-stream)
127 (setq start (with-current-buffer buffer (point-max)))
128 (process-send-string stream starttls-command)
129 (proto-stream-get-response stream start (proto-stream-eoc parameters))
130 (gnutls-negotiate stream nil)
131 ;; Re-get the capabilities, since they may have changed
132 ;; after switching to TLS.
133 (setq start (with-current-buffer buffer (point-max)))
134 (process-send-string stream capability-command)
135 (list stream greeting (proto-stream-get-response
136 stream start (proto-stream-eoc parameters))))
138 (delete-process stream)
139 (proto-stream-open-starttls name buffer host service parameters)))))))
141 (defun proto-stream-capabilities (stream command end-of-command)
142 (let ((start (with-current-buffer (process-buffer stream) (point-max))))
143 (process-send-string stream command)
144 (proto-stream-get-response stream start end-of-command)))
146 (defun proto-stream-open-starttls (name buffer host service parameters)
147 (proto-stream-capability-open
148 (with-current-buffer buffer (point))
149 (starttls-open-stream name buffer host service)
152 (defun proto-stream-get-response (stream start end-of-command)
153 (with-current-buffer (process-buffer stream)
156 (while (and (memq (process-status stream)
158 (not (re-search-forward end-of-command nil t)))
159 (accept-process-output stream 0 50)
161 (if (= start (point))
162 ;; The process died; return nil.
164 ;; Return the data we got back.
165 (buffer-substring start (point))))))
167 (defun proto-stream-open-tls (name buffer host service parameters)
168 (proto-stream-capability-open
169 (with-current-buffer buffer (point))
170 (funcall (if (fboundp 'open-gnutls-stream)
173 name buffer host service)
176 (defun proto-stream-open-shell (name buffer host service parameters)
177 (proto-stream-capability-open
178 (with-current-buffer buffer (point))
179 (let ((process-connection-type nil))
180 (start-process name buffer shell-file-name
183 (cadr (memq :shell-command parameters))
189 (defun proto-stream-capability-open (start stream parameters)
190 (let ((capability-command (cadr (memq :capability-command parameters)))
191 (greeting (proto-stream-get-response
192 stream start (proto-stream-eoc parameters))))
193 (list stream greeting
194 (and capability-command
195 (proto-stream-capabilities
196 stream capability-command
197 (proto-stream-eoc parameters))))))
199 (defun proto-stream-eoc (parameters)
200 (or (cadr (memq :end-of-command parameters))
203 (provide 'proto-stream)
205 ;;; proto-stream.el ends here