1 """TELNET client class.
3 Based on RFC 854: TELNET Protocol Specification, by J. Postel and
8 >>> from telnetlib import Telnet
9 >>> tn = Telnet('www.python.org', 79) # connect to finger port
10 >>> tn.write('guido\r\n')
11 >>> print tn.read_all()
12 Login Name TTY Idle When Where
13 guido Guido van Rossum pts/2 <Dec 2 11:10> snag.cnri.reston..
17 Note that read_all() won't read until eof -- it just reads some data
18 -- but it guarantees to read at least one byte unless EOF is hit.
20 It is possible to pass a Telnet object to select.select() in order to
21 wait until more data is available. Note that in this case,
22 read_eager() may return '' even if there was data on the socket,
23 because the protocol negotiation may have eaten the data. This is why
24 EOFError is needed in some cases to distinguish between "no data" and
25 "connection closed" (since the socket also appears ready for reading
30 - timeout should be intrinsic to the connection object instead of an
31 option on one of the read calls only
46 # Telnet protocol defaults
49 # Telnet protocol characters (don't change)
50 IAC = chr(255) # "Interpret As Command"
57 SE = chr(240) # Subnegotiation End
58 NOP = chr(241) # No Operation
59 DM = chr(242) # Data Mark
60 BRK = chr(243) # Break
61 IP = chr(244) # Interrupt process
62 AO = chr(245) # Abort output
63 AYT = chr(246) # Are You There
64 EC = chr(247) # Erase Character
65 EL = chr(248) # Erase Line
66 GA = chr(249) # Go Ahead
67 SB = chr(250) # Subnegotiation Begin
70 # Telnet protocol options code (don't change)
71 # These ones all come from arpa/telnet.h
72 BINARY = chr(0) # 8-bit data path
74 RCP = chr(2) # prepare to reconnect
75 SGA = chr(3) # suppress go ahead
76 NAMS = chr(4) # approximate message size
77 STATUS = chr(5) # give status
78 TM = chr(6) # timing mark
79 RCTE = chr(7) # remote controlled transmission and echo
80 NAOL = chr(8) # negotiate about output line width
81 NAOP = chr(9) # negotiate about output page size
82 NAOCRD = chr(10) # negotiate about CR disposition
83 NAOHTS = chr(11) # negotiate about horizontal tabstops
84 NAOHTD = chr(12) # negotiate about horizontal tab disposition
85 NAOFFD = chr(13) # negotiate about formfeed disposition
86 NAOVTS = chr(14) # negotiate about vertical tab stops
87 NAOVTD = chr(15) # negotiate about vertical tab disposition
88 NAOLFD = chr(16) # negotiate about output LF disposition
89 XASCII = chr(17) # extended ascii character set
90 LOGOUT = chr(18) # force logout
91 BM = chr(19) # byte macro
92 DET = chr(20) # data entry terminal
93 SUPDUP = chr(21) # supdup protocol
94 SUPDUPOUTPUT = chr(22) # supdup output
95 SNDLOC = chr(23) # send location
96 TTYPE = chr(24) # terminal type
97 EOR = chr(25) # end or record
98 TUID = chr(26) # TACACS user identification
99 OUTMRK = chr(27) # output marking
100 TTYLOC = chr(28) # terminal location number
101 VT3270REGIME = chr(29) # 3270 regime
102 X3PAD = chr(30) # X.3 PAD
103 NAWS = chr(31) # window size
104 TSPEED = chr(32) # terminal speed
105 LFLOW = chr(33) # remote flow control
106 LINEMODE = chr(34) # Linemode option
107 XDISPLOC = chr(35) # X Display Location
108 OLD_ENVIRON = chr(36) # Old - Environment variables
109 AUTHENTICATION = chr(37) # Authenticate
110 ENCRYPT = chr(38) # Encryption option
111 NEW_ENVIRON = chr(39) # New - Environment variables
112 # the following ones come from
113 # http://www.iana.org/assignments/telnet-options
114 # Unfortunately, that document does not assign identifiers
115 # to all of them, so we are making them up
116 TN3270E = chr(40) # TN3270E
117 XAUTH = chr(41) # XAUTH
118 CHARSET = chr(42) # CHARSET
119 RSP = chr(43) # Telnet Remote Serial Port
120 COM_PORT_OPTION = chr(44) # Com Port Control Option
121 SUPPRESS_LOCAL_ECHO = chr(45) # Telnet Suppress Local Echo
122 TLS = chr(46) # Telnet Start TLS
123 KERMIT = chr(47) # KERMIT
124 SEND_URL = chr(48) # SEND-URL
125 FORWARD_X = chr(49) # FORWARD_X
126 PRAGMA_LOGON = chr(138) # TELOPT PRAGMA LOGON
127 SSPI_LOGON = chr(139) # TELOPT SSPI LOGON
128 PRAGMA_HEARTBEAT = chr(140) # TELOPT PRAGMA HEARTBEAT
129 EXOPL = chr(255) # Extended-Options-List
134 """Telnet interface class.
136 An instance of this class represents a connection to a telnet
137 server. The instance is initially not connected; the open()
138 method must be used to establish a connection. Alternatively, the
139 host name and optional port number can be passed to the
142 Don't try to reopen an already connected instance.
144 This class has many read_*() methods. Note that some of them
145 raise EOFError when the end of the connection is read, because
146 they can return an empty string for other reasons. See the
147 individual doc strings.
149 read_until(expected, [timeout])
150 Read until the expected string has been seen, or a timeout is
151 hit (default is no timeout); may block.
154 Read all data until EOF; may block.
157 Read at least one byte or EOF; may block.
160 Read all data available already queued or on the socket,
164 Read either data already queued or some data available on the
165 socket, without blocking.
168 Read all data in the raw queue (processing it first), without
169 doing any socket I/O.
172 Reads all data in the cooked queue, without doing any socket
176 Reads available data between SB ... SE sequence. Don't block.
178 set_option_negotiation_callback(callback)
179 Each time a telnet option is read on the input flow, this callback
180 (if set) is called with the following parameters :
181 callback(telnet socket, command, option)
182 option will be chr(0) when there is no option.
183 No other action is done afterwards by telnetlib.
187 def __init__(self, host=None, port=0, timeout=None):
190 When called without arguments, create an unconnected instance.
191 With a hostname argument, it connects the instance; a port
192 number and connect timeout is optional.
195 self.debuglevel = DEBUGLEVEL
203 self.iacseq = '' # Buffer for IAC sequence.
204 self.sb = 0 # flag for SB and SE sequence.
206 self.option_callback = None
208 self.open(host, port, timeout)
210 def open(self, host, port=0, timeout=None):
211 """Connect to a host.
213 The optional second argument is the port number, which
214 defaults to the standard telnet port (23). The optional third
215 argument is a timeout in seconds; if None, the default timeout
216 of the underlying socket will be used.
218 Don't try to reopen an already connected instance.
226 msg = "getaddrinfo returns an empty list"
227 for res in socket.getaddrinfo(host, port, 0, socket.SOCK_STREAM):
228 af, socktype, proto, canonname, sa = res
230 self.sock = socket.socket(af, socktype, proto)
231 if timeout is not None:
232 self.sock.settimeout(timeout)
233 self.sock.connect(sa)
234 except socket.error, msg:
241 raise socket.error, msg
244 """Destructor -- close the connection."""
247 def msg(self, msg, *args):
248 """Print a debug message, when the debug level is > 0.
250 If extra arguments are present, they are substituted in the
251 message using the standard string formatting operator.
254 if self.debuglevel > 0:
255 print 'Telnet(%s,%d):' % (self.host, self.port),
261 def set_debuglevel(self, debuglevel):
262 """Set the debug level.
264 The higher it is, the more debug output you get (on sys.stdout).
267 self.debuglevel = debuglevel
270 """Close the connection."""
278 def get_socket(self):
279 """Return the socket object used internally."""
283 """Return the fileno() of the socket object used internally."""
284 return self.sock.fileno()
286 def write(self, buffer):
287 """Write a string to the socket, doubling any IAC characters.
289 Can block if the connection is blocked. May raise
290 socket.error if the connection is closed.
294 buffer = buffer.replace(IAC, IAC+IAC)
295 self.msg("send %s", `buffer`)
296 self.sock.sendall(buffer)
298 def read_until(self, match, timeout=None):
299 """Read until a given string is encountered or until timeout.
301 When no match is found, return whatever is available instead,
302 possibly the empty string. Raise EOFError if the connection
303 is closed and no cooked data is available.
308 i = self.cookedq.find(match)
311 buf = self.cookedq[:i]
312 self.cookedq = self.cookedq[i:]
314 s_reply = ([self], [], [])
316 if timeout is not None:
317 s_args = s_args + (timeout,)
318 while not self.eof and select.select(*s_args) == s_reply:
319 i = max(0, len(self.cookedq)-n)
322 i = self.cookedq.find(match, i)
325 buf = self.cookedq[:i]
326 self.cookedq = self.cookedq[i:]
328 return self.read_very_lazy()
331 """Read all data until EOF; block until connection closed."""
341 """Read at least one byte of cooked data unless EOF is hit.
343 Return '' if EOF is hit. Block if no data is immediately
348 while not self.cookedq and not self.eof:
355 def read_very_eager(self):
356 """Read everything that's possible without blocking in I/O (eager).
358 Raise EOFError if connection closed and no cooked data
359 available. Return '' if no cooked data available otherwise.
360 Don't block unless in the midst of an IAC sequence.
364 while not self.eof and self.sock_avail():
367 return self.read_very_lazy()
369 def read_eager(self):
370 """Read readily available data.
372 Raise EOFError if connection closed and no cooked data
373 available. Return '' if no cooked data available otherwise.
374 Don't block unless in the midst of an IAC sequence.
378 while not self.cookedq and not self.eof and self.sock_avail():
381 return self.read_very_lazy()
384 """Process and return data that's already in the queues (lazy).
386 Raise EOFError if connection closed and no data available.
387 Return '' if no cooked data available otherwise. Don't block
388 unless in the midst of an IAC sequence.
392 return self.read_very_lazy()
394 def read_very_lazy(self):
395 """Return any data available in the cooked queue (very lazy).
397 Raise EOFError if connection closed and no data available.
398 Return '' if no cooked data available otherwise. Don't block.
403 if not buf and self.eof and not self.rawq:
404 raise EOFError, 'telnet connection closed'
407 def read_sb_data(self):
408 """Return any data available in the SB ... SE queue.
410 Return '' if no SB ... SE available. Should only be called
411 after seeing a SB or SE command. When a new SB command is
412 found, old unread SB data will be discarded. Don't block.
419 def set_option_negotiation_callback(self, callback):
420 """Provide a callback function called after each receipt of a telnet option."""
421 self.option_callback = callback
423 def process_rawq(self):
424 """Transfer from raw queue to cooked queue.
426 Set self.eof when connection is closed. Don't block unless in
427 the midst of an IAC sequence.
433 c = self.rawq_getchar()
440 buf[self.sb] = buf[self.sb] + c
444 elif len(self.iacseq) == 1:
445 'IAC: IAC CMD [OPTION only for WILL/WONT/DO/DONT]'
446 if c in (DO, DONT, WILL, WONT):
452 buf[self.sb] = buf[self.sb] + c
454 if c == SB: # SB ... SE start.
459 self.sbdataq = self.sbdataq + buf[1]
461 if self.option_callback:
462 # Callback is supposed to look into
464 self.option_callback(self.sock, c, NOOPT)
466 # We can't offer automatic processing of
467 # suboptions. Alas, we should not get any
468 # unless we did a WILL/DO before.
469 self.msg('IAC %d not recognized' % ord(c))
470 elif len(self.iacseq) == 2:
474 if cmd in (DO, DONT):
475 self.msg('IAC %s %d',
476 cmd == DO and 'DO' or 'DONT', ord(opt))
477 if self.option_callback:
478 self.option_callback(self.sock, cmd, opt)
480 self.sock.sendall(IAC + WONT + opt)
481 elif cmd in (WILL, WONT):
482 self.msg('IAC %s %d',
483 cmd == WILL and 'WILL' or 'WONT', ord(opt))
484 if self.option_callback:
485 self.option_callback(self.sock, cmd, opt)
487 self.sock.sendall(IAC + DONT + opt)
488 except EOFError: # raised by self.rawq_getchar()
489 self.iacseq = '' # Reset on EOF
492 self.cookedq = self.cookedq + buf[0]
493 self.sbdataq = self.sbdataq + buf[1]
495 def rawq_getchar(self):
496 """Get next char from raw queue.
498 Block if no data is immediately available. Raise EOFError
499 when connection is closed.
506 c = self.rawq[self.irawq]
507 self.irawq = self.irawq + 1
508 if self.irawq >= len(self.rawq):
514 """Fill raw queue from exactly one recv() system call.
516 Block if no data is immediately available. Set self.eof when
517 connection is closed.
520 if self.irawq >= len(self.rawq):
523 # The buffer size should be fairly small so as to avoid quadratic
524 # behavior in process_rawq() above
525 buf = self.sock.recv(50)
526 self.msg("recv %s", `buf`)
528 self.rawq = self.rawq + buf
530 def sock_avail(self):
531 """Test whether data is available on the socket."""
532 return select.select([self], [], [], 0) == ([self], [], [])
535 """Interaction function, emulates a very dumb telnet client."""
536 if sys.platform == "win32":
540 rfd, wfd, xfd = select.select([self, sys.stdin], [], [])
543 text = self.read_eager()
545 print '*** Connection closed by remote host ***'
548 sys.stdout.write(text)
551 line = sys.stdin.readline()
556 def mt_interact(self):
557 """Multithreaded version of interact()."""
559 thread.start_new_thread(self.listener, ())
561 line = sys.stdin.readline()
567 """Helper for mt_interact() -- this executes in the other thread."""
570 data = self.read_eager()
572 print '*** Connection closed by remote host ***'
575 sys.stdout.write(data)
579 def expect(self, list, timeout=None):
580 """Read until one from a list of a regular expressions matches.
582 The first argument is a list of regular expressions, either
583 compiled (re.RegexObject instances) or uncompiled (strings).
584 The optional second argument is a timeout, in seconds; default
587 Return a tuple of three items: the index in the list of the
588 first regular expression that matches; the match object
589 returned; and the text read up till and including the match.
591 If EOF is read and no text was read, raise EOFError.
592 Otherwise, when nothing matches, return (-1, None, text) where
593 text is the text received so far (may be the empty string if a
596 If a regular expression ends with a greedy match (e.g. '.*')
597 or if more than one expression can match the same input, the
598 results are undeterministic, and may depend on the I/O timing.
603 indices = range(len(list))
605 if not hasattr(list[i], "search"):
607 list[i] = re.compile(list[i])
611 m = list[i].search(self.cookedq)
614 text = self.cookedq[:e]
615 self.cookedq = self.cookedq[e:]
619 if timeout is not None:
620 r, w, x = select.select([self.fileno()], [], [], timeout)
624 text = self.read_very_lazy()
625 if not text and self.eof:
627 return (-1, None, text)
631 """Test program for telnetlib.
633 Usage: python telnetlib.py [-d] ... [host [port]]
635 Default host is localhost; default port is 23.
639 while sys.argv[1:] and sys.argv[1] == '-d':
640 debuglevel = debuglevel+1
647 portstr = sys.argv[2]
651 port = socket.getservbyname(portstr, 'tcp')
653 tn.set_debuglevel(debuglevel)
658 if __name__ == '__main__':