lisp/net/tramp-gw.el

   1 ;;; tramp-gw.el --- Tramp utility functions for HTTP tunnels and SOCKS gateways
   2
   3 ;; Copyright (C) 2007 Free Software Foundation, Inc.
   4
   5 ;; Author: Michael Albinus <michael.albinus@gmx.de>
   6 ;; Keywords: comm, processes
   7
   8 ;; This file is part of GNU Emacs.
   9
  10 ;; GNU Emacs is free software; you can redistribute it and/or modify
  11 ;; it under the terms of the GNU General Public License as published by
  12 ;; the Free Software Foundation; either version 3, or (at your option)
  13 ;; any later version.
  14
  15 ;; GNU Emacs is distributed in the hope that it will be useful,
  16 ;; but WITHOUT ANY WARRANTY; without even the implied warranty of
  17 ;; MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
  18 ;; GNU General Public License for more details.
  19
  20 ;; You should have received a copy of the GNU General Public License
  21 ;; along with GNU Emacs; see the file COPYING.  If not, see
  22 ;; <http://www.gnu.org/licenses/>.
  23
  24 ;;; Commentary:
  25
  26 ;; Access functions for HTTP tunnels and SOCKS gateways from Tramp.
  27 ;; SOCKS functionality is implemented by socks.el from the w3 package.
  28 ;; HTTP tunnels are partly implemented in socks.el and url-http.el;
  29 ;; both implementations are not complete.  Therefore, it is
  30 ;; implemented in this package.
  31
  32 ;;; Code:
  33
  34 (require 'tramp)
  35
  36 ;; Pacify byte-compiler
  37 (eval-when-compile
  38   (require 'cl)
  39   (require 'custom))
  40
  41 ;; Autoload the socks library.  It is used only when we access a SOCKS server.
  42 (autoload 'socks-open-network-stream "socks")
  43 (defvar socks-username (user-login-name))
  44 (defvar socks-server (list "Default server" "socks" 1080 5))
  45
  46 ;; Avoid byte-compiler warnings if the byte-compiler supports this.
  47 ;; Currently, XEmacs supports this.
  48 (eval-when-compile
  49   (when (featurep 'xemacs)
  50       (byte-compiler-options (warnings (- unused-vars)))))
  51
  52 ;; Define HTTP tunnel method ...
  53 (defvar tramp-gw-tunnel-method "tunnel"
  54   "*Method to connect HTTP gateways.")
  55
  56 ;; ... and port.
  57 (defvar tramp-gw-default-tunnel-port 8080
  58   "*Default port for HTTP gateways.")
  59
  60 ;; Define SOCKS method ...
  61 (defvar tramp-gw-socks-method "socks"
  62   "*Method to connect SOCKS servers.")
  63
  64 ;; ... and port.
  65 (defvar tramp-gw-default-socks-port 1080
  66   "*Default port for SOCKS servers.")
  67
  68 ;; Add a default for `tramp-default-user-alist'.  Default is the local user.
  69 (add-to-list 'tramp-default-user-alist
  70              `(,tramp-gw-tunnel-method nil ,(user-login-name)))
  71 (add-to-list 'tramp-default-user-alist
  72              `(,tramp-gw-socks-method nil ,(user-login-name)))
  73
  74 ;; Internal file name functions and variables.
  75
  76 (defvar tramp-gw-vector nil
  77   "Keeps the remote host identification.  Needed for Tramp messages.")
  78
  79 (defvar tramp-gw-gw-vector nil
  80   "Current gateway identification vector.")
  81
  82 (defvar tramp-gw-gw-proc nil
  83   "Current gateway process.")
  84
  85 ;; This variable keeps the listening process, in order to reuse it for
  86 ;; new processes.
  87 (defvar tramp-gw-aux-proc nil
  88   "Process listening on local port, as mediation between SSH and the gateway.")
  89
  90 (defun tramp-gw-gw-proc-sentinel (proc event)
  91   "Delete auxiliary process when we are deleted."
  92   (unless (memq (process-status proc) '(run open))
  93     (tramp-message
  94      tramp-gw-vector 4 "Deleting auxiliary process `%s'" tramp-gw-gw-proc)
  95     (let* (tramp-verbose
  96            (p (tramp-get-connection-property proc "process" nil)))
  97       (when (processp p) (delete-process p)))))
  98
  99 (defun tramp-gw-aux-proc-sentinel (proc event)
 100   "Activate the different filters for involved gateway and auxiliary processes."
 101   (when (memq (process-status proc) '(run open))
 102     ;; A new process has been spawned from `tramp-gw-aux-proc'.
 103     (tramp-message
 104      tramp-gw-vector 4
 105      "Opening auxiliary process `%s', speaking with process `%s'"
 106      proc tramp-gw-gw-proc)
 107     (tramp-set-process-query-on-exit-flag proc nil)
 108     ;; We don't want debug messages, because the corresponding debug
 109     ;; buffer might be undecided.
 110     (let (tramp-verbose)
 111       (tramp-set-connection-property tramp-gw-gw-proc "process" proc)
 112       (tramp-set-connection-property proc "process" tramp-gw-gw-proc))
 113     ;; Set the process-filter functions for both processes.
 114     (set-process-filter proc 'tramp-gw-process-filter)
 115     (set-process-filter tramp-gw-gw-proc 'tramp-gw-process-filter)
 116     ;; There might be already some output from the gateway process.
 117     (with-current-buffer (process-buffer tramp-gw-gw-proc)
 118       (unless (= (point-min) (point-max))
 119         (let ((s (buffer-string)))
 120           (delete-region (point) (point-max))
 121           (tramp-gw-process-filter tramp-gw-gw-proc s))))))
 122
 123 (defun tramp-gw-process-filter (proc string)
 124   (let (tramp-verbose)
 125     (process-send-string
 126      (tramp-get-connection-property proc "process" nil) string)))
 127
 128 (defun tramp-gw-open-connection (vec gw-vec target-vec)
 129   "Open a remote connection to VEC (see `tramp-file-name' structure).
 130 Take GW-VEC as SOCKS or HTTP gateway, i.e. its method must be a
 131 gateway method.  TARGET-VEC identifies where to connect to via
 132 the gateway, it can be different from VEC when there are more
 133 hops to be applied.
 134
 135 It returns a string like \"localhost#port\", which must be used
 136 instead of the host name declared in TARGET-VEC."
 137
 138   ;; Remember vectors for property retrieval.
 139   (setq tramp-gw-vector vec
 140         tramp-gw-gw-vector gw-vec)
 141
 142   ;; Start listening auxiliary process.
 143   (unless (and (processp tramp-gw-aux-proc)
 144                (memq (process-status tramp-gw-aux-proc) '(listen)))
 145     (let ((aux-vec
 146            (vector "aux" (tramp-file-name-user gw-vec)
 147                    (tramp-file-name-host gw-vec) nil)))
 148       (setq tramp-gw-aux-proc
 149             (make-network-process
 150              :name (tramp-buffer-name aux-vec) :buffer nil :host 'local
 151              :server t :noquery t :service t :coding 'binary))
 152       (set-process-sentinel tramp-gw-aux-proc 'tramp-gw-aux-proc-sentinel)
 153       (tramp-set-process-query-on-exit-flag tramp-gw-aux-proc nil)
 154       (tramp-message
 155        vec 4 "Opening auxiliary process `%s', listening on port %d"
 156        tramp-gw-aux-proc (process-contact tramp-gw-aux-proc :service))))
 157
 158   (let* ((gw-method
 159           (intern
 160            (tramp-find-method
 161             (tramp-file-name-method gw-vec)
 162             (tramp-file-name-user gw-vec)
 163             (tramp-file-name-host gw-vec))))
 164          (socks-username
 165           (tramp-find-user
 166            (tramp-file-name-method gw-vec)
 167            (tramp-file-name-user gw-vec)
 168            (tramp-file-name-host gw-vec)))
 169          ;; Declare the SOCKS server to be used.
 170          (socks-server
 171           (list "Tramp tempory socks server list"
 172                 ;; Host name.
 173                 (tramp-file-name-real-host gw-vec)
 174                 ;; Port number.
 175                 (or (tramp-file-name-port gw-vec)
 176                     (case gw-method
 177                       (tunnel tramp-gw-default-tunnel-port)
 178                       (socks tramp-gw-default-socks-port)))
 179                 ;; Type.  We support only http and socks5, NO socks4.
 180                 ;; 'http could be used when HTTP tunnel works in socks.el.
 181                 5))
 182          ;; The function to be called.
 183          (socks-function
 184           (case gw-method
 185             (tunnel 'tramp-gw-open-network-stream)
 186             (socks 'socks-open-network-stream)))
 187          socks-noproxy)
 188
 189     ;; Open SOCKS process.
 190     (setq tramp-gw-gw-proc
 191           (funcall
 192            socks-function
 193            (tramp-buffer-name gw-vec)
 194            (tramp-get-buffer gw-vec)
 195            (tramp-file-name-real-host target-vec)
 196            (tramp-file-name-port target-vec)))
 197     (set-process-sentinel tramp-gw-gw-proc 'tramp-gw-gw-proc-sentinel)
 198     (tramp-set-process-query-on-exit-flag tramp-gw-gw-proc nil)
 199     (tramp-message
 200      vec 4 "Opened %s process `%s'"
 201      (case gw-method ('tunnel "HTTP tunnel") ('socks "SOCKS"))
 202      tramp-gw-gw-proc)
 203
 204     ;; Return the new host for gateway access.
 205     (format "localhost#%d" (process-contact tramp-gw-aux-proc :service))))
 206
 207 (defun tramp-gw-open-network-stream (name buffer host service)
 208   "Open stream to proxy server HOST:SERVICE.
 209 Resulting process has name NAME and buffer BUFFER.  If
 210 authentication is requested from proxy server, provide it."
 211   (let ((command (format (concat
 212                           "CONNECT %s:%d HTTP/1.1\r\n"
 213                           "Host: %s:%d\r\n"
 214                           "Connection: keep-alive\r\n"
 215                           "User-Agent: Tramp/%s\r\n")
 216                          host service host service tramp-version))
 217         (authentication "")
 218         (first t)
 219         found proc)
 220
 221     (while (not found)
 222       ;; Clean up.
 223       (when (processp proc) (delete-process proc))
 224       (with-current-buffer buffer (erase-buffer))
 225       ;; Open network stream.
 226       (setq proc (open-network-stream
 227                   name buffer (nth 1 socks-server) (nth 2 socks-server)))
 228       (set-process-coding-system proc 'binary 'binary)
 229       (tramp-set-process-query-on-exit-flag proc nil)
 230       ;; Send CONNECT command.
 231       (process-send-string proc (format "%s%s\r\n" command authentication))
 232       (tramp-message
 233        tramp-gw-vector 6 "\n%s"
 234        (format
 235         "%s%s\r\n" command
 236         (replace-regexp-in-string ;; no password in trace!
 237          "Basic [^\r\n]+" "Basic xxxxx" authentication t)))
 238       (with-current-buffer buffer
 239         ;; Trap errors to be traced in the right trace buffer.  Often,
 240         ;; proxies have a timeout of 60".  We wait 65" in order to
 241         ;; receive an answer this case.
 242         (condition-case nil
 243             (let (tramp-verbose)
 244               (tramp-wait-for-regexp proc 65 "\r?\n\r?\n"))
 245           (error nil))
 246         ;; Check return code.
 247         (goto-char (point-min))
 248         (narrow-to-region
 249          (point-min)
 250          (or (search-forward-regexp "\r?\n\r?\n" nil t) (point-max)))
 251         (tramp-message tramp-gw-vector 6 "\n%s" (buffer-string))
 252         (goto-char (point-min))
 253         (search-forward-regexp "^HTTP/[1-9]\\.[0-9]" nil t)
 254         (case (condition-case nil (read (current-buffer)) (error))
 255           ;; Connected.
 256           (200 (setq found t))
 257           ;; We need basic authentication.
 258           (401 (setq authentication (tramp-gw-basic-authentication nil first)))
 259           ;; Target host not found.
 260           (404 (tramp-error-with-buffer
 261                 (current-buffer) tramp-gw-vector 'file-error
 262                 "Host %s not found." host))
 263           ;; We need basic proxy authentication.
 264           (407 (setq authentication (tramp-gw-basic-authentication t first)))
 265           ;; Connection failed.
 266           (503 (tramp-error-with-buffer
 267                 (current-buffer) tramp-gw-vector 'file-error
 268                 "Connection to %s:%d failed." host service))
 269           ;; That doesn't work at all.
 270           (t (tramp-error-with-buffer
 271               (current-buffer) tramp-gw-vector 'file-error
 272               "Access to HTTP server %s:%d failed."
 273               (nth 1 socks-server) (nth 2 socks-server))))
 274         ;; Remove HTTP headers.
 275         (delete-region (point-min) (point-max))
 276         (widen)
 277         (setq first nil)))
 278     ;; Return the process.
 279     proc))
 280
 281 (defun tramp-gw-basic-authentication (proxy pw-cache)
 282   "Return authentication header for CONNECT, based on server request.
 283 PROXY is an indication whether we need a Proxy-Authorization header
 284 or an Authorization header.  If PW-CACHE is non-nil, check for
 285 password in password cache.  This is done for the first try only."
 286
 287   ;; `tramp-current-*' must be set for `tramp-read-passwd'.
 288   (let ((tramp-current-method (tramp-file-name-method tramp-gw-gw-vector))
 289         (tramp-current-user (tramp-file-name-user tramp-gw-gw-vector))
 290         (tramp-current-host (tramp-file-name-host tramp-gw-gw-vector)))
 291     (unless pw-cache (tramp-clear-passwd tramp-gw-gw-vector))
 292     ;; We are already in the right buffer.
 293     (tramp-message
 294      tramp-gw-vector 5 "%s required"
 295      (if proxy "Proxy authentication" "Authentication"))
 296     ;; Search for request header.  We accept only basic authentication.
 297     (goto-char (point-min))
 298     (search-forward-regexp
 299      "^\\(Proxy\\|WWW\\)-Authenticate:\\s-*Basic\\s-+realm=")
 300     ;; Return authentication string.
 301     (format
 302      "%s: Basic %s\r\n"
 303      (if proxy "Proxy-Authorization" "Authorization")
 304      (base64-encode-string
 305       (format
 306        "%s:%s"
 307        socks-username
 308        (tramp-read-passwd
 309         nil
 310         (format
 311          "Password for %s@[%s]: " socks-username (read (current-buffer)))))))))
 312
 313
 314 (provide 'tramp-gw)
 315
 316 ;;; TODO:
 317
 318 ;; * Provide descriptive Commentary.
 319 ;; * Enable it for several gateway processes in parallel.
 320
 321 ;; arch-tag: 277e3a81-fdee-40cf-9e6b-59626292a5e0
 322 ;;; tramp-gw.el ends here