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<title>filter_in (TelnetFilter)</title>
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<pre><span class="ruby-comment cmt"># File lib/network/protocol/telnetfilter.rb, line 83</span>
<span class="ruby-keyword kw">def</span> <span class="ruby-identifier">filter_in</span>(<span class="ruby-identifier">str</span>)
<span class="ruby-comment cmt"># init_subneg</span>
<span class="ruby-keyword kw">return</span> <span class="ruby-value str">""</span> <span class="ruby-keyword kw">if</span> <span class="ruby-identifier">str</span>.<span class="ruby-identifier">nil?</span> <span class="ruby-operator">||</span> <span class="ruby-identifier">str</span>.<span class="ruby-identifier">empty?</span>
<span class="ruby-identifier">buf</span> = <span class="ruby-value str">""</span>
<span class="ruby-ivar">@sc</span> <span class="ruby-operator">?</span> <span class="ruby-ivar">@sc</span>.<span class="ruby-identifier">concat</span>(<span class="ruby-identifier">str</span>) <span class="ruby-operator">:</span> <span class="ruby-ivar">@sc</span> = <span class="ruby-constant">StringScanner</span>.<span class="ruby-identifier">new</span>(<span class="ruby-identifier">str</span>)
<span class="ruby-keyword kw">while</span> <span class="ruby-identifier">b</span> = <span class="ruby-ivar">@sc</span>.<span class="ruby-identifier">get_byte</span>
<span class="ruby-comment cmt"># OOB sync data</span>
<span class="ruby-keyword kw">if</span> <span class="ruby-ivar">@pstack</span>.<span class="ruby-identifier">urgent_on</span> <span class="ruby-operator">||</span> <span class="ruby-identifier">b</span>[<span class="ruby-value">0</span>] <span class="ruby-operator">==</span> <span class="ruby-constant">DM</span>
<span class="ruby-identifier">log</span>.<span class="ruby-identifier">debug</span>(<span class="ruby-node">"(#{@pstack.conn.object_id}) Sync mode on"</span>)
<span class="ruby-ivar">@pstack</span>.<span class="ruby-identifier">urgent_on</span> = <span class="ruby-keyword kw">false</span>
<span class="ruby-ivar">@synch</span> = <span class="ruby-keyword kw">true</span>
<span class="ruby-keyword kw">break</span>
<span class="ruby-keyword kw">end</span>
<span class="ruby-keyword kw">case</span> <span class="ruby-identifier">mode?</span>
<span class="ruby-keyword kw">when</span> <span class="ruby-identifier">:normal</span>
<span class="ruby-keyword kw">case</span> <span class="ruby-identifier">b</span>[<span class="ruby-value">0</span>]
<span class="ruby-keyword kw">when</span> <span class="ruby-constant">CR</span>
<span class="ruby-keyword kw">next</span> <span class="ruby-keyword kw">if</span> <span class="ruby-ivar">@synch</span>
<span class="ruby-identifier">set_mode</span>(<span class="ruby-identifier">:cr</span>) <span class="ruby-keyword kw">if</span> <span class="ruby-operator">!</span><span class="ruby-ivar">@pstack</span>.<span class="ruby-identifier">binary_on</span>
<span class="ruby-keyword kw">when</span> <span class="ruby-constant">LF</span> <span class="ruby-comment cmt"># LF or LF/CR may be issued by broken mud servers and clients</span>
<span class="ruby-keyword kw">next</span> <span class="ruby-keyword kw">if</span> <span class="ruby-ivar">@synch</span>
<span class="ruby-identifier">set_mode</span>(<span class="ruby-identifier">:lf</span>) <span class="ruby-keyword kw">if</span> <span class="ruby-operator">!</span><span class="ruby-ivar">@pstack</span>.<span class="ruby-identifier">binary_on</span>
<span class="ruby-identifier">buf</span> <span class="ruby-operator"><<</span> <span class="ruby-constant">LF</span>.<span class="ruby-identifier">chr</span>
<span class="ruby-identifier">echo</span>(<span class="ruby-constant">CR</span>.<span class="ruby-identifier">chr</span> <span class="ruby-operator">+</span> <span class="ruby-constant">LF</span>.<span class="ruby-identifier">chr</span>)
<span class="ruby-keyword kw">when</span> <span class="ruby-constant">IAC</span>
<span class="ruby-identifier">set_mode</span>(<span class="ruby-identifier">:cmd</span>)
<span class="ruby-keyword kw">when</span> <span class="ruby-constant">NUL</span> <span class="ruby-comment cmt"># ignore NULs in stream when in normal mode</span>
<span class="ruby-keyword kw">next</span> <span class="ruby-keyword kw">if</span> <span class="ruby-ivar">@synch</span>
<span class="ruby-keyword kw">if</span> <span class="ruby-ivar">@pstack</span>.<span class="ruby-identifier">binary_on</span>
<span class="ruby-identifier">buf</span> <span class="ruby-operator"><<</span> <span class="ruby-identifier">b</span>
<span class="ruby-identifier">echo</span>(<span class="ruby-identifier">b</span>)
<span class="ruby-keyword kw">else</span>
<span class="ruby-identifier">log</span>.<span class="ruby-identifier">debug</span>(<span class="ruby-node">"(#{@pstack.conn.object_id}) unexpected NUL found in stream"</span>)
<span class="ruby-keyword kw">end</span>
<span class="ruby-keyword kw">when</span> <span class="ruby-constant">BS</span>, <span class="ruby-constant">DEL</span>
<span class="ruby-keyword kw">next</span> <span class="ruby-keyword kw">if</span> <span class="ruby-ivar">@synch</span>
<span class="ruby-comment cmt"># Leaves BS, DEL in input stream for higher filter to deal with.</span>
<span class="ruby-identifier">buf</span> <span class="ruby-operator"><<</span> <span class="ruby-identifier">b</span>
<span class="ruby-identifier">echo</span>(<span class="ruby-constant">BS</span>.<span class="ruby-identifier">chr</span>)
<span class="ruby-keyword kw">else</span>
<span class="ruby-keyword kw">next</span> <span class="ruby-keyword kw">if</span> <span class="ruby-ivar">@synch</span>
<span class="ruby-comment cmt">### NOTE - we will allow 8-bit NVT against RFC 1123 recommendation "should not"</span>
<span class="ruby-comment cmt">###</span>
<span class="ruby-comment cmt"># Only let 7-bit values through in normal mode</span>
<span class="ruby-comment cmt">#if (b[0] & 0x80 == 0) && !@pstack.binary_on</span>
<span class="ruby-identifier">buf</span> <span class="ruby-operator"><<</span> <span class="ruby-identifier">b</span>
<span class="ruby-identifier">echo</span>(<span class="ruby-identifier">b</span>)
<span class="ruby-comment cmt">#else</span>
<span class="ruby-comment cmt"># log.debug("(#{@pstack.conn.object_id}) unexpected 8-bit byte found in stream '#{b[0]}'")</span>
<span class="ruby-comment cmt">#end</span>
<span class="ruby-keyword kw">end</span>
<span class="ruby-keyword kw">when</span> <span class="ruby-identifier">:cr</span>
<span class="ruby-comment cmt"># handle CRLF and CRNUL by insertion of LF into buffer</span>
<span class="ruby-keyword kw">case</span> <span class="ruby-identifier">b</span>[<span class="ruby-value">0</span>]
<span class="ruby-keyword kw">when</span> <span class="ruby-constant">LF</span>
<span class="ruby-identifier">buf</span> <span class="ruby-operator"><<</span> <span class="ruby-constant">LF</span>.<span class="ruby-identifier">chr</span>
<span class="ruby-identifier">echo</span>(<span class="ruby-constant">CR</span>.<span class="ruby-identifier">chr</span> <span class="ruby-operator">+</span> <span class="ruby-constant">LF</span>.<span class="ruby-identifier">chr</span>)
<span class="ruby-keyword kw">when</span> <span class="ruby-constant">NUL</span>
<span class="ruby-keyword kw">if</span> <span class="ruby-ivar">@server</span>.<span class="ruby-identifier">service_type</span> <span class="ruby-operator">==</span> <span class="ruby-identifier">:client</span> <span class="ruby-comment cmt"># Don't xlate CRNUL when client</span>
<span class="ruby-identifier">buf</span> <span class="ruby-operator"><<</span> <span class="ruby-constant">CR</span>.<span class="ruby-identifier">chr</span>
<span class="ruby-identifier">echo</span>(<span class="ruby-constant">CR</span>.<span class="ruby-identifier">chr</span>)
<span class="ruby-keyword kw">else</span>
<span class="ruby-identifier">buf</span> <span class="ruby-operator"><<</span> <span class="ruby-constant">LF</span>.<span class="ruby-identifier">chr</span>
<span class="ruby-identifier">echo</span>(<span class="ruby-constant">CR</span>.<span class="ruby-identifier">chr</span> <span class="ruby-operator">+</span> <span class="ruby-constant">LF</span>.<span class="ruby-identifier">chr</span>)
<span class="ruby-keyword kw">end</span>
<span class="ruby-keyword kw">else</span> <span class="ruby-comment cmt"># eat lone CR</span>
<span class="ruby-identifier">buf</span> <span class="ruby-operator"><<</span> <span class="ruby-identifier">b</span>
<span class="ruby-identifier">echo</span>(<span class="ruby-identifier">b</span>)
<span class="ruby-keyword kw">end</span>
<span class="ruby-identifier">set_mode</span>(<span class="ruby-identifier">:normal</span>)
<span class="ruby-keyword kw">when</span> <span class="ruby-identifier">:lf</span>
<span class="ruby-comment cmt"># liberally handle LF, LFCR for clients that aren't telnet correct</span>
<span class="ruby-keyword kw">case</span> <span class="ruby-identifier">b</span>[<span class="ruby-value">0</span>]
<span class="ruby-keyword kw">when</span> <span class="ruby-constant">CR</span> <span class="ruby-comment cmt"># Handle LFCR by swallowing CR</span>
<span class="ruby-keyword kw">else</span> <span class="ruby-comment cmt"># Handle other stuff that follows - single LF</span>
<span class="ruby-identifier">buf</span> <span class="ruby-operator"><<</span> <span class="ruby-identifier">b</span>
<span class="ruby-identifier">echo</span>(<span class="ruby-identifier">b</span>)
<span class="ruby-keyword kw">end</span>
<span class="ruby-identifier">set_mode</span>(<span class="ruby-identifier">:normal</span>)
<span class="ruby-keyword kw">when</span> <span class="ruby-identifier">:cmd</span>
<span class="ruby-keyword kw">case</span> <span class="ruby-identifier">b</span>[<span class="ruby-value">0</span>]
<span class="ruby-keyword kw">when</span> <span class="ruby-constant">IAC</span>
<span class="ruby-comment cmt"># IAC escapes IAC</span>
<span class="ruby-identifier">buf</span> <span class="ruby-operator"><<</span> <span class="ruby-constant">IAC</span>.<span class="ruby-identifier">chr</span>
<span class="ruby-identifier">set_mode</span>(<span class="ruby-identifier">:normal</span>)
<span class="ruby-keyword kw">when</span> <span class="ruby-constant">AYT</span>
<span class="ruby-identifier">log</span>.<span class="ruby-identifier">debug</span>(<span class="ruby-node">"(#{@pstack.conn.object_id}) AYT sent - Msg returned"</span>)
<span class="ruby-ivar">@pstack</span>.<span class="ruby-identifier">conn</span>.<span class="ruby-identifier">sock</span>.<span class="ruby-identifier">send</span>(<span class="ruby-value str">"TeensyMUD is here.\n"</span>,<span class="ruby-value">0</span>)
<span class="ruby-identifier">set_mode</span>(<span class="ruby-identifier">:normal</span>)
<span class="ruby-keyword kw">when</span> <span class="ruby-constant">AO</span>
<span class="ruby-identifier">log</span>.<span class="ruby-identifier">debug</span>(<span class="ruby-node">"(#{@pstack.conn.object_id}) AO sent - Synch returned"</span>)
<span class="ruby-ivar">@pstack</span>.<span class="ruby-identifier">conn</span>.<span class="ruby-identifier">sockio</span>.<span class="ruby-identifier">write_flush</span>
<span class="ruby-ivar">@pstack</span>.<span class="ruby-identifier">conn</span>.<span class="ruby-identifier">sock</span>.<span class="ruby-identifier">send</span>(<span class="ruby-constant">IAC</span>.<span class="ruby-identifier">chr</span> <span class="ruby-operator">+</span> <span class="ruby-constant">DM</span>.<span class="ruby-identifier">chr</span>, <span class="ruby-value">0</span>)
<span class="ruby-ivar">@pstack</span>.<span class="ruby-identifier">conn</span>.<span class="ruby-identifier">sockio</span>.<span class="ruby-identifier">write_urgent</span>(<span class="ruby-constant">DM</span>.<span class="ruby-identifier">chr</span>)
<span class="ruby-identifier">set_mode</span>(<span class="ruby-identifier">:normal</span>)
<span class="ruby-keyword kw">when</span> <span class="ruby-constant">IP</span>
<span class="ruby-ivar">@pstack</span>.<span class="ruby-identifier">conn</span>.<span class="ruby-identifier">sockio</span>.<span class="ruby-identifier">read_flush</span>
<span class="ruby-ivar">@pstack</span>.<span class="ruby-identifier">conn</span>.<span class="ruby-identifier">sockio</span>.<span class="ruby-identifier">write_flush</span>
<span class="ruby-identifier">log</span>.<span class="ruby-identifier">debug</span>(<span class="ruby-node">"(#{@pstack.conn.object_id}) IP sent"</span>)
<span class="ruby-identifier">set_mode</span>(<span class="ruby-identifier">:normal</span>)
<span class="ruby-keyword kw">when</span> <span class="ruby-constant">GA</span>, <span class="ruby-constant">NOP</span>, <span class="ruby-constant">BRK</span> <span class="ruby-comment cmt"># not implemented or ignored</span>
<span class="ruby-identifier">log</span>.<span class="ruby-identifier">debug</span>(<span class="ruby-node">"(#{@pstack.conn.object_id}) GA, NOP or BRK sent"</span>)
<span class="ruby-identifier">set_mode</span>(<span class="ruby-identifier">:normal</span>)
<span class="ruby-keyword kw">when</span> <span class="ruby-constant">DM</span>
<span class="ruby-identifier">log</span>.<span class="ruby-identifier">debug</span>(<span class="ruby-node">"(#{@pstack.conn.object_id}) Synch mode off"</span>)
<span class="ruby-ivar">@synch</span> = <span class="ruby-keyword kw">false</span>
<span class="ruby-identifier">set_mode</span>(<span class="ruby-identifier">:normal</span>)
<span class="ruby-keyword kw">when</span> <span class="ruby-constant">EC</span>
<span class="ruby-keyword kw">next</span> <span class="ruby-keyword kw">if</span> <span class="ruby-ivar">@synch</span>
<span class="ruby-identifier">log</span>.<span class="ruby-identifier">debug</span>(<span class="ruby-node">"(#{@pstack.conn.object_id}) EC sent"</span>)
<span class="ruby-keyword kw">if</span> <span class="ruby-identifier">buf</span>.<span class="ruby-identifier">size</span> <span class="ruby-operator">></span> <span class="ruby-value">1</span>
<span class="ruby-identifier">buf</span>.<span class="ruby-identifier">slice!</span>(<span class="ruby-value">-1</span>)
<span class="ruby-keyword kw">elsif</span> <span class="ruby-ivar">@pstack</span>.<span class="ruby-identifier">conn</span>.<span class="ruby-identifier">inbuffer</span>.<span class="ruby-identifier">size</span> <span class="ruby-operator">></span> <span class="ruby-value">0</span>
<span class="ruby-ivar">@pstack</span>.<span class="ruby-identifier">conn</span>.<span class="ruby-identifier">inbuffer</span>.<span class="ruby-identifier">slice</span>(<span class="ruby-value">-1</span>)
<span class="ruby-keyword kw">end</span>
<span class="ruby-identifier">set_mode</span>(<span class="ruby-identifier">:normal</span>)
<span class="ruby-keyword kw">when</span> <span class="ruby-constant">EL</span>
<span class="ruby-keyword kw">next</span> <span class="ruby-keyword kw">if</span> <span class="ruby-ivar">@synch</span>
<span class="ruby-identifier">log</span>.<span class="ruby-identifier">debug</span>(<span class="ruby-node">"(#{@pstack.conn.object_id}) EL sent"</span>)
<span class="ruby-identifier">p</span> = <span class="ruby-identifier">buf</span>.<span class="ruby-identifier">rindex</span>(<span class="ruby-value str">"\n"</span>)
<span class="ruby-keyword kw">if</span> <span class="ruby-identifier">p</span>
<span class="ruby-identifier">buf</span>.<span class="ruby-identifier">slice!</span>(<span class="ruby-identifier">p</span><span class="ruby-operator">+</span><span class="ruby-value">1</span><span class="ruby-operator">..</span><span class="ruby-value">-1</span>)
<span class="ruby-keyword kw">else</span>
<span class="ruby-identifier">buf</span> = <span class="ruby-value str">""</span>
<span class="ruby-identifier">p</span> = <span class="ruby-ivar">@pstack</span>.<span class="ruby-identifier">conn</span>.<span class="ruby-identifier">inbuffer</span>.<span class="ruby-identifier">rindex</span>(<span class="ruby-value str">"\n"</span>)
<span class="ruby-keyword kw">if</span> <span class="ruby-identifier">p</span>
<span class="ruby-ivar">@pstack</span>.<span class="ruby-identifier">conn</span>.<span class="ruby-identifier">inbuffer</span>.<span class="ruby-identifier">slice!</span>(<span class="ruby-identifier">p</span><span class="ruby-operator">+</span><span class="ruby-value">1</span><span class="ruby-operator">..</span><span class="ruby-value">-1</span>)
<span class="ruby-keyword kw">end</span>
<span class="ruby-keyword kw">end</span>
<span class="ruby-identifier">set_mode</span>(<span class="ruby-identifier">:normal</span>)
<span class="ruby-keyword kw">when</span> <span class="ruby-constant">DO</span>, <span class="ruby-constant">DONT</span>, <span class="ruby-constant">WILL</span>, <span class="ruby-constant">WONT</span>
<span class="ruby-keyword kw">if</span> <span class="ruby-ivar">@sc</span>.<span class="ruby-identifier">eos?</span>
<span class="ruby-ivar">@sc</span>.<span class="ruby-identifier">unscan</span>
<span class="ruby-keyword kw">break</span>
<span class="ruby-keyword kw">end</span>
<span class="ruby-identifier">opt</span> = <span class="ruby-ivar">@sc</span>.<span class="ruby-identifier">get_byte</span>
<span class="ruby-keyword kw">case</span> <span class="ruby-identifier">b</span>[<span class="ruby-value">0</span>]
<span class="ruby-keyword kw">when</span> <span class="ruby-constant">WILL</span>
<span class="ruby-identifier">replies_him</span>(<span class="ruby-identifier">opt</span>[<span class="ruby-value">0</span>],<span class="ruby-keyword kw">true</span>)
<span class="ruby-keyword kw">when</span> <span class="ruby-constant">WONT</span>
<span class="ruby-identifier">replies_him</span>(<span class="ruby-identifier">opt</span>[<span class="ruby-value">0</span>],<span class="ruby-keyword kw">false</span>)
<span class="ruby-keyword kw">when</span> <span class="ruby-constant">DO</span>
<span class="ruby-identifier">requests_us</span>(<span class="ruby-identifier">opt</span>[<span class="ruby-value">0</span>],<span class="ruby-keyword kw">true</span>)
<span class="ruby-keyword kw">when</span> <span class="ruby-constant">DONT</span>
<span class="ruby-identifier">requests_us</span>(<span class="ruby-identifier">opt</span>[<span class="ruby-value">0</span>],<span class="ruby-keyword kw">false</span>)
<span class="ruby-keyword kw">end</span>
<span class="ruby-comment cmt"># Update interesting things in ProtocolStack after negotiation</span>
<span class="ruby-keyword kw">case</span> <span class="ruby-identifier">opt</span>[<span class="ruby-value">0</span>]
<span class="ruby-keyword kw">when</span> <span class="ruby-constant">ECHO</span>
<span class="ruby-ivar">@pstack</span>.<span class="ruby-identifier">echo_on</span> = <span class="ruby-identifier">enabled?</span>(<span class="ruby-constant">ECHO</span>, <span class="ruby-identifier">:us</span>)
<span class="ruby-keyword kw">when</span> <span class="ruby-constant">BINARY</span>
<span class="ruby-ivar">@pstack</span>.<span class="ruby-identifier">binary_on</span> = <span class="ruby-identifier">enabled?</span>(<span class="ruby-constant">BINARY</span>, <span class="ruby-identifier">:us</span>)
<span class="ruby-keyword kw">when</span> <span class="ruby-constant">ZMP</span>
<span class="ruby-ivar">@pstack</span>.<span class="ruby-identifier">zmp_on</span> = <span class="ruby-identifier">enabled?</span>(<span class="ruby-constant">ZMP</span>, <span class="ruby-identifier">:us</span>)
<span class="ruby-keyword kw">end</span>
<span class="ruby-identifier">set_mode</span>(<span class="ruby-identifier">:normal</span>)
<span class="ruby-keyword kw">when</span> <span class="ruby-constant">SB</span>
<span class="ruby-ivar">@sc</span>.<span class="ruby-identifier">unscan</span>
<span class="ruby-keyword kw">break</span> <span class="ruby-keyword kw">if</span> <span class="ruby-ivar">@sc</span>.<span class="ruby-identifier">check_until</span>(<span class="ruby-node">/#{IAC.chr}#{SE.chr}/</span>).<span class="ruby-identifier">nil?</span>
<span class="ruby-ivar">@sc</span>.<span class="ruby-identifier">get_byte</span>
<span class="ruby-identifier">opt</span> = <span class="ruby-ivar">@sc</span>.<span class="ruby-identifier">get_byte</span>
<span class="ruby-identifier">data</span> = <span class="ruby-ivar">@sc</span>.<span class="ruby-identifier">scan_until</span>(<span class="ruby-node">/#{IAC.chr}#{SE.chr}/</span>).<span class="ruby-identifier">chop</span>.<span class="ruby-identifier">chop</span>
<span class="ruby-identifier">parse_subneg</span>(<span class="ruby-identifier">opt</span>[<span class="ruby-value">0</span>],<span class="ruby-identifier">data</span>)
<span class="ruby-identifier">set_mode</span>(<span class="ruby-identifier">:normal</span>)
<span class="ruby-keyword kw">else</span>
<span class="ruby-identifier">log</span>.<span class="ruby-identifier">debug</span>(<span class="ruby-node">"(#{@pstack.conn.object_id}) Unknown Telnet command - #{b[0]}"</span>)
<span class="ruby-identifier">set_mode</span>(<span class="ruby-identifier">:normal</span>)
<span class="ruby-keyword kw">end</span>
<span class="ruby-keyword kw">end</span>
<span class="ruby-keyword kw">end</span> <span class="ruby-comment cmt"># while b</span>
<span class="ruby-ivar">@sc</span> = <span class="ruby-keyword kw">nil</span> <span class="ruby-keyword kw">if</span> <span class="ruby-ivar">@sc</span>.<span class="ruby-identifier">eos?</span>
<span class="ruby-identifier">buf</span>
<span class="ruby-keyword kw">end</span></pre>
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