lisp/net/tramp-gw.el

   1 ;;; tramp-gw.el --- Tramp utility functions for HTTP tunnels and SOCKS gateways
   2
   3 ;; Copyright (C) 2007-2014 Free Software Foundation, Inc.
   4
   5 ;; Author: Michael Albinus <michael.albinus@gmx.de>
   6 ;; Keywords: comm, processes
   7 ;; Package: tramp
   8
   9 ;; This file is part of GNU Emacs.
  10
  11 ;; GNU Emacs is free software: you can redistribute it and/or modify
  12 ;; it under the terms of the GNU General Public License as published by
  13 ;; the Free Software Foundation, either version 3 of the License, or
  14 ;; (at your option) any later version.
  15
  16 ;; GNU Emacs is distributed in the hope that it will be useful,
  17 ;; but WITHOUT ANY WARRANTY; without even the implied warranty of
  18 ;; MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
  19 ;; GNU General Public License for more details.
  20
  21 ;; You should have received a copy of the GNU General Public License
  22 ;; along with GNU Emacs.  If not, see <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 (defvar socks-noproxy)
  41
  42 ;; We don't add the following methods to `tramp-methods', in order to
  43 ;; exclude them from file name completion.
  44
  45 ;; Define HTTP tunnel method ...
  46 ;;;###tramp-autoload
  47 (defconst tramp-gw-tunnel-method "tunnel"
  48   "Method to connect HTTP gateways.")
  49
  50 ;; ... and port.
  51 (defconst tramp-gw-default-tunnel-port 8080
  52   "Default port for HTTP gateways.")
  53
  54 ;; Define SOCKS method ...
  55 ;;;###tramp-autoload
  56 (defconst tramp-gw-socks-method "socks"
  57   "Method to connect SOCKS servers.")
  58
  59 ;; ... and port.
  60 (defconst tramp-gw-default-socks-port 1080
  61   "Default port for SOCKS servers.")
  62
  63 ;; Autoload the socks library.  It is used only when we access a SOCKS server.
  64 (autoload 'socks-open-network-stream "socks")
  65 (defvar socks-username (user-login-name))
  66 (defvar socks-server
  67   (list "Default server" "socks" tramp-gw-default-socks-port 5))
  68
  69 ;; Add a default for `tramp-default-user-alist'.  Default is the local user.
  70 ;;;###tramp-autoload
  71 (add-to-list
  72  'tramp-default-user-alist
  73  (list (concat "\\`"
  74                (regexp-opt (list tramp-gw-tunnel-method tramp-gw-socks-method))
  75                "\\'")
  76        nil (user-login-name)))
  77
  78 ;; Internal file name functions and variables.
  79
  80 (defvar tramp-gw-vector nil
  81   "Keeps the remote host identification.  Needed for Tramp messages.")
  82
  83 (defvar tramp-gw-gw-vector nil
  84   "Current gateway identification vector.")
  85
  86 (defvar tramp-gw-gw-proc nil
  87   "Current gateway process.")
  88
  89 ;; This variable keeps the listening process, in order to reuse it for
  90 ;; new processes.
  91 (defvar tramp-gw-aux-proc nil
  92   "Process listening on local port, as mediation between SSH and the gateway.")
  93
  94 (defun tramp-gw-gw-proc-sentinel (proc _event)
  95   "Delete auxiliary process when we are deleted."
  96   (unless (memq (process-status proc) '(run open))
  97     (tramp-message
  98      tramp-gw-vector 4 "Deleting auxiliary process `%s'" tramp-gw-gw-proc)
  99     (let* ((tramp-verbose 0)
 100            (p (tramp-get-connection-property proc "process" nil)))
 101       (when (processp p) (delete-process p)))))
 102
 103 (defun tramp-gw-aux-proc-sentinel (proc _event)
 104   "Activate the different filters for involved gateway and auxiliary processes."
 105   (when (memq (process-status proc) '(run open))
 106     ;; A new process has been spawned from `tramp-gw-aux-proc'.
 107     (tramp-message
 108      tramp-gw-vector 4
 109      "Opening auxiliary process `%s', speaking with process `%s'"
 110      proc tramp-gw-gw-proc)
 111     (tramp-compat-set-process-query-on-exit-flag proc nil)
 112     ;; We don't want debug messages, because the corresponding debug
 113     ;; buffer might be undecided.
 114     (let ((tramp-verbose 0))
 115       (tramp-set-connection-property tramp-gw-gw-proc "process" proc)
 116       (tramp-set-connection-property proc "process" tramp-gw-gw-proc))
 117     ;; Set the process-filter functions for both processes.
 118     (set-process-filter proc 'tramp-gw-process-filter)
 119     (set-process-filter tramp-gw-gw-proc 'tramp-gw-process-filter)
 120     ;; There might be already some output from the gateway process.
 121     (with-current-buffer (process-buffer tramp-gw-gw-proc)
 122       (unless (= (point-min) (point-max))
 123         (let ((s (buffer-string)))
 124           (delete-region (point) (point-max))
 125           (tramp-gw-process-filter tramp-gw-gw-proc s))))))
 126
 127 (defun tramp-gw-process-filter (proc string)
 128   (let ((tramp-verbose 0))
 129     (process-send-string
 130      (tramp-get-connection-property proc "process" nil) string)))
 131
 132 ;;;###tramp-autoload
 133 (defun tramp-gw-open-connection (vec gw-vec target-vec)
 134   "Open a remote connection to VEC (see `tramp-file-name' structure).
 135 Take GW-VEC as SOCKS or HTTP gateway, i.e. its method must be a
 136 gateway method.  TARGET-VEC identifies where to connect to via
 137 the gateway, it can be different from VEC when there are more
 138 hops to be applied.
 139
 140 It returns a string like \"localhost#port\", which must be used
 141 instead of the host name declared in TARGET-VEC."
 142
 143   ;; Remember vectors for property retrieval.
 144   (setq tramp-gw-vector vec
 145         tramp-gw-gw-vector gw-vec)
 146
 147   ;; Start listening auxiliary process.
 148   (unless (and (processp tramp-gw-aux-proc)
 149                (memq (process-status tramp-gw-aux-proc) '(listen)))
 150     (let ((aux-vec
 151            (vector "aux" (tramp-file-name-user gw-vec)
 152                    (tramp-file-name-host gw-vec) nil nil)))
 153       (setq tramp-gw-aux-proc
 154             (make-network-process
 155              :name (tramp-buffer-name aux-vec) :buffer nil :host 'local
 156              :server t :noquery t :service t :coding 'binary))
 157       (set-process-sentinel tramp-gw-aux-proc 'tramp-gw-aux-proc-sentinel)
 158       (tramp-compat-set-process-query-on-exit-flag tramp-gw-aux-proc nil)
 159       (tramp-message
 160        vec 4 "Opening auxiliary process `%s', listening on port %d"
 161        tramp-gw-aux-proc (process-contact tramp-gw-aux-proc :service))))
 162
 163   (let* ((gw-method
 164           (intern
 165            (tramp-find-method
 166             (tramp-file-name-method gw-vec)
 167             (tramp-file-name-user gw-vec)
 168             (tramp-file-name-host gw-vec))))
 169          (socks-username
 170           (tramp-find-user
 171            (tramp-file-name-method gw-vec)
 172            (tramp-file-name-user gw-vec)
 173            (tramp-file-name-host gw-vec)))
 174          ;; Declare the SOCKS server to be used.
 175          (socks-server
 176           (list "Tramp temporary socks server list"
 177                 ;; Host name.
 178                 (tramp-file-name-real-host gw-vec)
 179                 ;; Port number.
 180                 (or (tramp-file-name-port gw-vec)
 181                     (case gw-method
 182                       (tunnel tramp-gw-default-tunnel-port)
 183                       (socks tramp-gw-default-socks-port)))
 184                 ;; Type.  We support only http and socks5, NO socks4.
 185                 ;; 'http could be used when HTTP tunnel works in socks.el.
 186                 5))
 187          ;; The function to be called.
 188          (socks-function
 189           (case gw-method
 190             (tunnel 'tramp-gw-open-network-stream)
 191             (socks 'socks-open-network-stream)))
 192          socks-noproxy)
 193
 194     ;; Open SOCKS process.
 195     (setq tramp-gw-gw-proc
 196           (funcall
 197            socks-function
 198            (tramp-get-connection-name gw-vec)
 199            (tramp-get-connection-buffer gw-vec)
 200            (tramp-file-name-real-host target-vec)
 201            (tramp-file-name-port target-vec)))
 202     (set-process-sentinel tramp-gw-gw-proc 'tramp-gw-gw-proc-sentinel)
 203     (tramp-compat-set-process-query-on-exit-flag tramp-gw-gw-proc nil)
 204     (tramp-message
 205      vec 4 "Opened %s process `%s'"
 206      (case gw-method ('tunnel "HTTP tunnel") ('socks "SOCKS"))
 207      tramp-gw-gw-proc)
 208
 209     ;; Return the new host for gateway access.
 210     (format "localhost#%d" (process-contact tramp-gw-aux-proc :service))))
 211
 212 (defun tramp-gw-open-network-stream (name buffer host service)
 213   "Open stream to proxy server HOST:SERVICE.
 214 Resulting process has name NAME and buffer BUFFER.  If
 215 authentication is requested from proxy server, provide it."
 216   (let ((command (format (concat
 217                           "CONNECT %s:%d HTTP/1.1\r\n"
 218                           "Host: %s:%d\r\n"
 219                           "Connection: keep-alive\r\n"
 220                           "User-Agent: Tramp/%s\r\n")
 221                          host service host service tramp-version))
 222         (authentication "")
 223         (first t)
 224         found proc)
 225
 226     (while (not found)
 227       ;; Clean up.
 228       (when (processp proc) (delete-process proc))
 229       (with-current-buffer buffer (erase-buffer))
 230       ;; Open network stream.
 231       (setq proc (open-network-stream
 232                   name buffer (nth 1 socks-server) (nth 2 socks-server)))
 233       (set-process-coding-system proc 'binary 'binary)
 234       (tramp-compat-set-process-query-on-exit-flag proc nil)
 235       ;; Send CONNECT command.
 236       (process-send-string proc (format "%s%s\r\n" command authentication))
 237       (tramp-message
 238        tramp-gw-vector 6 "\n%s"
 239        (format
 240         "%s%s\r\n" command
 241         (tramp-compat-replace-regexp-in-string ;; no password in trace!
 242          "Basic [^\r\n]+" "Basic xxxxx" authentication t)))
 243       (with-current-buffer buffer
 244         ;; Trap errors to be traced in the right trace buffer.  Often,
 245         ;; proxies have a timeout of 60".  We wait 65" in order to
 246         ;; receive an answer this case.
 247         (ignore-errors
 248           (let ((tramp-verbose 0))
 249             (tramp-wait-for-regexp proc 65 "\r?\n\r?\n")))
 250         ;; Check return code.
 251         (goto-char (point-min))
 252         (narrow-to-region
 253          (point-min)
 254          (or (search-forward-regexp "\r?\n\r?\n" nil t) (point-max)))
 255         (tramp-message tramp-gw-vector 6 "\n%s" (buffer-string))
 256         (goto-char (point-min))
 257         (search-forward-regexp "^HTTP/[1-9]\\.[0-9]" nil t)
 258         (case (condition-case nil (read (current-buffer)) (error))
 259           ;; Connected.
 260           (200 (setq found t))
 261           ;; We need basic authentication.
 262           (401 (setq authentication (tramp-gw-basic-authentication nil first)))
 263           ;; Target host not found.
 264           (404 (tramp-error-with-buffer
 265                 (current-buffer) tramp-gw-vector 'file-error
 266                 "Host %s not found." host))
 267           ;; We need basic proxy authentication.
 268           (407 (setq authentication (tramp-gw-basic-authentication t first)))
 269           ;; Connection failed.
 270           (503 (tramp-error-with-buffer
 271                 (current-buffer) tramp-gw-vector 'file-error
 272                 "Connection to %s:%d failed." host service))
 273           ;; That doesn't work at all.
 274           (t (tramp-error-with-buffer
 275               (current-buffer) tramp-gw-vector 'file-error
 276               "Access to HTTP server %s:%d failed."
 277               (nth 1 socks-server) (nth 2 socks-server))))
 278         ;; Remove HTTP headers.
 279         (delete-region (point-min) (point-max))
 280         (widen)
 281         (setq first nil)))
 282     ;; Return the process.
 283     proc))
 284
 285 (defun tramp-gw-basic-authentication (proxy pw-cache)
 286   "Return authentication header for CONNECT, based on server request.
 287 PROXY is an indication whether we need a Proxy-Authorization header
 288 or an Authorization header.  If PW-CACHE is non-nil, check for
 289 password in password cache.  This is done for the first try only."
 290
 291   ;; `tramp-current-*' must be set for `tramp-read-passwd'.
 292   (let ((tramp-current-method (tramp-file-name-method tramp-gw-gw-vector))
 293         (tramp-current-user (tramp-file-name-user tramp-gw-gw-vector))
 294         (tramp-current-host (tramp-file-name-host tramp-gw-gw-vector)))
 295     (unless pw-cache (tramp-clear-passwd tramp-gw-gw-vector))
 296     ;; We are already in the right buffer.
 297     (tramp-message
 298      tramp-gw-vector 5 "%s required"
 299      (if proxy "Proxy authentication" "Authentication"))
 300     ;; Search for request header.  We accept only basic authentication.
 301     (goto-char (point-min))
 302     (search-forward-regexp
 303      "^\\(Proxy\\|WWW\\)-Authenticate:\\s-*Basic\\s-+realm=")
 304     ;; Return authentication string.
 305     (format
 306      "%s: Basic %s\r\n"
 307      (if proxy "Proxy-Authorization" "Authorization")
 308      (base64-encode-string
 309       (format
 310        "%s:%s"
 311        socks-username
 312        (tramp-read-passwd
 313         nil
 314         (format
 315          "Password for %s@[%s]: " socks-username (read (current-buffer)))))))))
 316
 317 (add-hook 'tramp-unload-hook
 318           (lambda ()
 319             (unload-feature 'tramp-gw 'force)))
 320
 321 (provide 'tramp-gw)
 322
 323 ;;; TODO:
 324
 325 ;; * Provide descriptive Commentary.
 326 ;; * Enable it for several gateway processes in parallel.
 327
 328 ;;; tramp-gw.el ends here