1 # -*- coding: utf-8 -*-
2 """Telnet functions and constants for the mudpy engine."""
4 # Copyright (c) 2004-2012 Jeremy Stanley <fungi@yuggoth.org>. Permission
5 # to use, copy, modify, and distribute this software is granted under
6 # terms provided in the LICENSE file distributed with this software.
8 # telnet options (from bsd's arpa/telnet.h since telnetlib's are ambiguous)
9 TELOPT_BINARY = 0 # transmit 8-bit data by the receiver (rfc 856)
10 TELOPT_ECHO = 1 # echo received data back to the sender (rfc 857)
11 TELOPT_SGA = 3 # suppress transmission of the go ahead character (rfc 858)
12 # TELOPT_TTYPE = 24 # exchange terminal type information (rfc 1091)
13 TELOPT_EOR = 25 # transmit end-of-record after transmitting data (rfc 885)
14 TELOPT_NAWS = 31 # negotiate about window size (rfc 1073)
15 TELOPT_LINEMODE = 34 # cooked line-by-line input mode (rfc 1184)
27 EOR = 239 # end-of-record signal (rfc 885)
28 SE = 240 # end of subnegotiation parameters (rfc 854)
29 GA = 249 # go ahead signal (rfc 854)
30 SB = 250 # what follows is subnegotiation of the indicated option (rfc 854)
31 WILL = 251 # desire or confirmation of performing an option (rfc 854)
32 WONT = 252 # refusal or confirmation of performing an option (rfc 854)
33 DO = 253 # request or confirm performing an option (rfc 854)
34 DONT = 254 # demand or confirm no longer performing an option (rfc 854)
35 IAC = 255 # interpret as command escape character (rfc 854)
37 # RFC 1143 option negotiation states
38 NO = 0 # option is disabled
39 YES = 1 # option is enabled
40 WANTNO = 2 # demanded disabling option
41 WANTYES = 3 # requested enabling option
42 WANTNO_OPPOSITE = 4 # demanded disabling option but queued an enable after it
43 WANTYES_OPPOSITE = 5 # requested enabling option but queued a disable after it
45 # RFC 1143 option negotiation parties
50 def telnet_proto(*arguments):
51 """Return a concatenated series of Telnet protocol commands."""
52 # (this will need to be byte type during 2to3 migration)
53 return "".join([chr(x) for x in arguments])
56 def send_command(user, *command):
57 """Sends a Telnet command string to the specified user's socket."""
58 user.send(telnet_proto(IAC, *command), raw=True)
61 def is_enabled(user, telopt, party, state=YES):
62 """Returns True if the indicated Telnet option is enabled, False if
64 if (telopt, party) in user.telopts and user.telopts[
72 def enable(user, telopt, party):
73 """Negotiates enabling a Telnet option for the indicated user's socket."""
78 if not (telopt, party) in user.telopts or user.telopts[
81 user.telopts[(telopt, party)] = WANTYES
82 send_command(user, txpos, telopt)
83 elif user.telopts[(telopt, party)] is WANTNO:
84 user.telopts[(telopt, party)] = WANTNO_OPPOSITE
85 elif user.telopts[(telopt, party)] is WANTYES_OPPOSITE:
86 user.telopts[(telopt, party)] = WANTYES
89 def disable(user, telopt, party):
90 """Negotiates disabling a Telnet option for the indicated user's
96 if not (telopt, party) in user.telopts:
97 user.telopts[(telopt, party)] = NO
98 elif user.telopts[(telopt, party)] is YES:
99 user.telopts[(telopt, party)] = WANTNO
100 send_command(user, txneg, telopt)
101 elif user.telopts[(telopt, party)] is WANTYES:
102 user.telopts[(telopt, party)] = WANTYES_OPPOSITE
103 elif user.telopts[(telopt, party)] is WANTNO_OPPOSITE:
104 user.telopts[(telopt, party)] = WANTNO
107 def negotiate_telnet_options(user):
108 """Reply to and remove telnet negotiation options from partial_input."""
111 # make a local copy to play with
112 text = user.partial_input
114 # start at the begining of the input
117 # as long as we haven't checked it all
119 while position < len_text:
121 # jump to the first IAC you find
122 position = text.find(telnet_proto(IAC), position)
124 # if there wasn't an IAC in the input or it's at the end, we're done
125 if position < 0 or position >= len_text - 1:
128 # the byte following the IAC is our command
129 # (this will need to be byte type during 2to3 migration)
130 command = ord(text[position + 1])
132 # replace a double (literal) IAC if there's an LF later
134 if text.find("\n", position) > 0:
136 text = text[:position] + text[position + 1:]
140 # implement an RFC 1143 option negotiation queue here
141 elif len_text > position + 2 and WILL <= command <= DONT:
142 # this will need to be byte type during 2to3 migration
143 telopt = ord(text[position + 2])
144 if telopt in supported:
155 if (telopt, party) not in user.telopts:
156 user.telopts[(telopt, party)] = NO
158 if user.telopts[(telopt, party)] is NO:
159 user.telopts[(telopt, party)] = YES
160 send_command(user, txpos, telopt)
161 elif user.telopts[(telopt, party)] is WANTNO:
162 user.telopts[(telopt, party)] = NO
163 elif user.telopts[(telopt, party)] is WANTNO_OPPOSITE:
164 user.telopts[(telopt, party)] = YES
165 elif user.telopts[(telopt, party)] is WANTYES_OPPOSITE:
166 user.telopts[(telopt, party)] = WANTNO
167 send_command(user, txneg, telopt)
169 user.telopts[(telopt, party)] = YES
171 if user.telopts[(telopt, party)] is YES:
172 user.telopts[(telopt, party)] = NO
173 send_command(user, txneg, telopt)
174 elif user.telopts[(telopt, party)] is WANTNO_OPPOSITE:
175 user.telopts[(telopt, party)] = WANTYES
176 send_command(user, txpos, telopt)
178 user.telopts[(telopt, party)] = NO
179 elif command is WILL:
180 send_command(user, DONT, telopt)
182 send_command(user, WONT, telopt)
183 text = text[:position] + text[position + 3:]
185 # subnegotiation options
186 elif len_text > position + 4 and command is SB:
187 # this will need to be byte type during 2to3 migration
188 telopt = ord(text[position + 2])
189 if telopt is TELOPT_NAWS:
190 # this will need to be byte type during 2to3 migration
191 user.columns = ord(text[position + 3]) * \
192 256 + ord(text[position + 4])
193 end_subnegotiation = text.find(telnet_proto(IAC, SE), position)
194 if end_subnegotiation > 0:
195 text = text[:position] + text[end_subnegotiation + 2:]
199 # otherwise, strip out a two-byte IAC command
200 elif len_text > position + 2:
201 misc.log("Unknown Telnet IAC command %s ignored." % command)
202 text = text[:position] + text[position + 2:]
204 # and this means we got the begining of an IAC
208 # replace the input with our cleaned-up text
209 user.partial_input = text