From ab10720260e2c184b319026da89f4dfd338500bb Mon Sep 17 00:00:00 2001
From: Brian Cully <bjc@kublai.com>
Date: Wed, 2 Apr 2008 19:20:20 -0400
Subject: Initial commit

---
 PlugIns/Telnet.lisp | 149 ++++++++++++++++++++++++++++++++++++++++++++++++++++
 1 file changed, 149 insertions(+)
 create mode 100644 PlugIns/Telnet.lisp

(limited to 'PlugIns/Telnet.lisp')

diff --git a/PlugIns/Telnet.lisp b/PlugIns/Telnet.lisp
new file mode 100644
index 0000000..2410af4
--- /dev/null
+++ b/PlugIns/Telnet.lisp
@@ -0,0 +1,149 @@
+;; -*- Lisp -*-
+;; $Id: Telnet.lisp 20 2005-12-27 15:21:23Z bjc $
+
+(defpackage telnet-options
+  (:use :cl :cl-user :moxie :bjc-utils))
+(in-package :telnet-options)
+
+(defconstant +iac+ 255
+  "Interpret as Command")
+
+(defconstant +se+ 240
+  "End of subnegotiation parameters.")
+
+(defconstant +nop+ 241
+  "No operation.")
+
+(defconstant +data-mark+ 242
+  "The data stream portion of a Synch.
+This should always be accompanied
+by a TCP Urgent notification.")
+
+(defconstant +break+ 243
+  "NVT character BRK.")
+
+(defconstant +interrupt-process+ 244
+  "The function IP.")
+
+(defconstant +abort-output+ 245
+  "The function AO.")
+
+(defconstant +are-you-there+ 246
+  "The function AYT.")
+
+(defconstant +erase-character+ 247
+  "The function EC.")
+
+(defconstant +erase-line+ 248
+  "The function EL.")
+
+(defconstant +go-ahead+ 249
+  "The GA signal.")
+
+(defconstant +sb+ 250
+  "Indicates that what follows is
+subnegotiation of the indicated option.")
+
+(defconstant +will+ 251
+  "Indicates the desire to begin
+performing, or confirmation that
+you are now performing, the
+indicated option.")
+
+(defconstant +wont+ 252
+  "Indicates the refusal to perform,
+or continue performing, the
+indicated option.")
+
+(defconstant +do+ 253
+  "Indicates the request that the
+other party perform, or
+confirmation that you are expecting
+the other party to perform, the
+indicated option.")
+
+(defconstant +dont+ 254
+  "Indicates the demand tha the
+other party stop performing,
+or confirmation that you are no
+longer expecting the other party
+to perform, the indicated option.")
+
+(defconstant +option-binary+ 0
+  "Enable binary (8 bit) data transmission, instead of the stripped 7 bit ASCII default.")
+(defconstant +option-echo+ 1
+  "Enable remote echo, suppressing local echo.")
+(defconstant +option-supress-go-ahead+ 3
+  "Enable go-ahead suppression.")
+(defconstant +option-status+ 5
+  "Enable option spamming for easier negotiations.")
+(defconstant +option-timing-mark+ 6
+  "Return a timing mark when this is recieved.")
+(defconstant +option-terminal+ 24
+  "Return terminal type.")
+(defconstant +option-window-size+ 31
+  "Negotiate about window size.")
+(defconstant +option-authentication+ 37
+  "Negotiate authentication.")
+(defconstant +option-environment+ 39
+  "Negotiate environment variables.")
+(defconstant +option-extended-options-list+ 255
+  "Read the next byte for further options.")
+
+(defconstant +option-mccp1+ 85
+  "Mud Client Compression Protocol version 1.")
+(defconstant +option-mccp2+ 86
+  "Mud Client Compression Protocol version 2.")
+(defconstant +option-msp+ 90
+  "Mud Sound Protocol.")
+(defconstant +option-mxp+ 91
+  "Mud eXtension Protocol.")
+
+(defun ack-cmd (cmd)
+  "Computes the ACK code for CMD."
+  (cond ((eql cmd +do+) +will+)
+        ((eql cmd +will+) +do+)
+        ((eql cmd +dont+) +wont+)
+        ((eql cmd +wont+) +dont+)))
+
+(defun nack-cmd (cmd)
+  "Computes the NACK code for CMD."
+  (cond ((eql cmd +do+) +wont+)
+        ((eql cmd +will+) +dont+)
+        ((eql cmd +dont+) +will+)
+        ((eql cmd +wont+) +do+)))
+
+(defun send-option (cmd option)
+  (let ((options (world-var 'options)))
+    (unless options
+      (setf (world-var 'options) (make-hash-table))
+      (setf options (world-var 'options)))
+    (unless (eql cmd (gethash option options))
+      (setf (gethash option options) cmd)
+      (send-bytes (list +iac+ cmd option)))))
+
+(defun send-bytes (bytes)
+  (write-array-to-mux *world* bytes))
+
+(defun handle-command-array (array)
+  "Array is a byte-vector of the complete IAC code, including any IAC characters."
+  (format t "(handle-command-array ~S)~%" array)
+  (when (and (> (length array) 1) (eql (elt array 0) +iac+))
+    (let ((cmd (elt array 1)))
+      (cond ((or (eql cmd +do+) (eql cmd +will+))
+             (awhen (aand (> (length array) 2) (elt array 2))
+               (cond ((eql it +option-timing-mark+)
+                      (send-bytes (list +iac+ ack-cmd cmd) it))
+                     ((or (eql it +option-binary+)
+                          (eql it +option-supress-go-ahead+)
+                          (eql it +option-status+)
+                          (eql it +option-msp+)
+                          (eql it +option-mxp+))
+                      (send-option (ack-cmd cmd) it))
+                     (t (send-option (nack-cmd cmd) it)))))
+            ((or (eql cmd +dont+) (eql cmd +wont+))
+             (awhen (aand (> (length array) 2) (elt array 2))
+               (send-option (ack-cmd cmd) it)))
+            (t (format t "Can't handle command ~S.~%" cmd))))))
+
+(add-hook 'handle-command-array :telnet-option-hook)
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