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<title>Class: Net::SSH::Transport::IncomingPacketStream</title>
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<td class="file-title"><span class="file-title-prefix">Class</span><br />Net::SSH::Transport::IncomingPacketStream</td>
<td align="right">
<table cellspacing=0 cellpadding=2>
<tr valign="top">
<td>In:</td>
<td>
<a href="../../../../files/lib/net/ssh/transport/packet-stream_rb.html">lib/net/ssh/transport/packet-stream.rb</a>
</td>
</tr>
<tr>
<td>Parent:</td>
<td>
<a href="PacketStream.html">
PacketStream
</a>
</td>
</tr>
</table>
</td>
</tr>
</table>
<!-- banner header -->
<div id="bodyContent">
<div id="content">
<div class="description"><p>
Handles the decompression and dencryption of incoming packets.
</p>
</div>
<div class="sectiontitle">Methods</div>
<ul>
<li><a href="#M000069">get</a></li>
<li><a href="#M000067">new</a></li>
<li><a href="#M000068">set_algorithms</a></li>
</ul>
<div class="sectiontitle">Attributes</div>
<table border='0' cellpadding='5'>
<tr valign='top'>
<td class='attr-rw'>
[W]
</td>
<td class='attr-name'>buffers</td>
<td class='attr-desc'>
A handle to the buffer factory to use when creating buffers
</td>
</tr>
<tr valign='top'>
<td class='attr-rw'>
[W]
</td>
<td class='attr-name'>log</td>
<td class='attr-desc'>
A handle to the logger instance to use for writing log messages
</td>
</tr>
</table>
<div class="sectiontitle">Public Class methods</div>
<div class="method">
<div class="title">
<a name="M000067"></a><b>new</b>( ciphers, hmacs, decompressors )
</div>
<div class="description">
<p>
Create a <a href="IncomingPacketStream.html#M000067">new</a> <a
href="IncomingPacketStream.html">IncomingPacketStream</a>.
</p>
</div>
<div class="sourcecode">
<p class="source-link">[ <a href="javascript:toggleSource('M000067_source')" id="l_M000067_source">show source</a> ]</p>
<div id="M000067_source" class="dyn-source">
<pre>
<span class="ruby-comment cmt"># File lib/net/ssh/transport/packet-stream.rb, line 141</span>
141: <span class="ruby-keyword kw">def</span> <span class="ruby-identifier">initialize</span>( <span class="ruby-identifier">ciphers</span>, <span class="ruby-identifier">hmacs</span>, <span class="ruby-identifier">decompressors</span> )
142: <span class="ruby-keyword kw">super</span>( <span class="ruby-identifier">ciphers</span>, <span class="ruby-identifier">hmacs</span> )
143: <span class="ruby-ivar">@decompressor</span> = <span class="ruby-identifier">decompressors</span>.<span class="ruby-identifier">fetch</span>( <span class="ruby-value str">"none"</span> )
144: <span class="ruby-ivar">@mutex</span> = <span class="ruby-constant">Mutex</span>.<span class="ruby-identifier">new</span>
145: <span class="ruby-keyword kw">end</span>
</pre>
</div>
</div>
</div>
<div class="sectiontitle">Public Instance methods</div>
<div class="method">
<div class="title">
<a name="M000069"></a><b>get</b>()
</div>
<div class="description">
<p>
Retrieve the next packet from the string, after (possibly) decrypting and
decompressing it. The packet is returned as a reader buffer.
</p>
</div>
<div class="sourcecode">
<p class="source-link">[ <a href="javascript:toggleSource('M000069_source')" id="l_M000069_source">show source</a> ]</p>
<div id="M000069_source" class="dyn-source">
<pre>
<span class="ruby-comment cmt"># File lib/net/ssh/transport/packet-stream.rb, line 155</span>
155: <span class="ruby-keyword kw">def</span> <span class="ruby-identifier">get</span>
156: <span class="ruby-ivar">@mutex</span>.<span class="ruby-identifier">synchronize</span> <span class="ruby-keyword kw">do</span>
157: <span class="ruby-comment cmt"># get the first block of data</span>
158: <span class="ruby-keyword kw">if</span> <span class="ruby-ivar">@log</span>.<span class="ruby-identifier">debug?</span>
159: <span class="ruby-ivar">@log</span>.<span class="ruby-identifier">debug</span> <span class="ruby-node">"reading #{@cipher.block_size} bytes from socket..."</span>
160: <span class="ruby-keyword kw">end</span>
161:
162: <span class="ruby-identifier">data</span> = <span class="ruby-identifier">read</span>( <span class="ruby-ivar">@cipher</span>.<span class="ruby-identifier">block_size</span> )
163:
164: <span class="ruby-comment cmt"># decipher it</span>
165: <span class="ruby-identifier">reader</span> = <span class="ruby-ivar">@buffers</span>.<span class="ruby-identifier">reader</span>( <span class="ruby-ivar">@cipher</span>.<span class="ruby-identifier">update</span>( <span class="ruby-identifier">data</span> ) )
166:
167: <span class="ruby-comment cmt"># determine the packet length and how many bytes remain to be read</span>
168: <span class="ruby-identifier">packet_length</span> = <span class="ruby-identifier">reader</span>.<span class="ruby-identifier">read_long</span>
169: <span class="ruby-identifier">remaining_to_read</span> = <span class="ruby-identifier">packet_length</span> <span class="ruby-operator">+</span> <span class="ruby-value">4</span> <span class="ruby-operator">-</span> <span class="ruby-ivar">@cipher</span>.<span class="ruby-identifier">block_size</span>
170: <span class="ruby-keyword kw">if</span> <span class="ruby-ivar">@log</span>.<span class="ruby-identifier">debug?</span>
171: <span class="ruby-ivar">@log</span>.<span class="ruby-identifier">debug</span> <span class="ruby-node">"packet length(#{packet_length}) "</span> <span class="ruby-operator">+</span>
172: <span class="ruby-node">"remaining(#{remaining_to_read})"</span>
173: <span class="ruby-keyword kw">end</span>
174:
175: <span class="ruby-comment cmt"># read the remainder of the packet and decrypt it.</span>
176: <span class="ruby-identifier">data</span> = <span class="ruby-identifier">read</span>( <span class="ruby-identifier">remaining_to_read</span> )
177:
178: <span class="ruby-comment cmt"># get the hmac from the tail of the packet (if one exists), and</span>
179: <span class="ruby-comment cmt"># then validate it.</span>
180: <span class="ruby-identifier">hmac</span> = <span class="ruby-ivar">@hmac</span>.<span class="ruby-identifier">mac_length</span> <span class="ruby-operator">></span> <span class="ruby-value">0</span> <span class="ruby-operator">?</span> <span class="ruby-identifier">read</span>( <span class="ruby-ivar">@hmac</span>.<span class="ruby-identifier">mac_length</span> ) <span class="ruby-operator">:</span> <span class="ruby-value str">""</span>
181:
182: <span class="ruby-identifier">reader</span>.<span class="ruby-identifier">append</span> <span class="ruby-ivar">@cipher</span>.<span class="ruby-identifier">update</span>( <span class="ruby-identifier">data</span> ) <span class="ruby-keyword kw">unless</span> <span class="ruby-identifier">data</span>.<span class="ruby-identifier">empty?</span>
183: <span class="ruby-identifier">reader</span>.<span class="ruby-identifier">append</span> <span class="ruby-ivar">@cipher</span>.<span class="ruby-identifier">final</span>
184:
185: <span class="ruby-identifier">padding_length</span> = <span class="ruby-identifier">reader</span>.<span class="ruby-identifier">read_byte</span>
186:
187: <span class="ruby-identifier">payload</span> = <span class="ruby-identifier">reader</span>.<span class="ruby-identifier">read</span>( <span class="ruby-identifier">packet_length</span> <span class="ruby-operator">-</span> <span class="ruby-identifier">padding_length</span> <span class="ruby-operator">-</span> <span class="ruby-value">1</span> )
188: <span class="ruby-identifier">padding</span> = <span class="ruby-identifier">reader</span>.<span class="ruby-identifier">read</span>( <span class="ruby-identifier">padding_length</span> ) <span class="ruby-keyword kw">if</span> <span class="ruby-identifier">padding_length</span> <span class="ruby-operator">></span> <span class="ruby-value">0</span>
189:
190: <span class="ruby-identifier">my_computed_hmac</span> = <span class="ruby-identifier">compute_hmac</span>( <span class="ruby-identifier">reader</span>.<span class="ruby-identifier">content</span> )
191: <span class="ruby-identifier">raise</span> <span class="ruby-constant">Net</span><span class="ruby-operator">::</span><span class="ruby-constant">SSH</span><span class="ruby-operator">::</span><span class="ruby-constant">Exception</span>, <span class="ruby-value str">"corrupted mac detected"</span> <span class="ruby-keyword kw">if</span> <span class="ruby-identifier">hmac</span> <span class="ruby-operator">!=</span> <span class="ruby-identifier">my_computed_hmac</span>
192:
193: <span class="ruby-comment cmt"># decompress the payload</span>
194: <span class="ruby-identifier">payload</span> = <span class="ruby-ivar">@decompressor</span>.<span class="ruby-identifier">decompress</span>( <span class="ruby-identifier">payload</span> )
195:
196: <span class="ruby-identifier">increment_sequence_number</span>
197:
198: <span class="ruby-identifier">buffer</span> = <span class="ruby-ivar">@buffers</span>.<span class="ruby-identifier">reader</span>( <span class="ruby-identifier">payload</span> )
199: <span class="ruby-ivar">@log</span>.<span class="ruby-identifier">debug</span> <span class="ruby-node">"received: #{buffer.content.inspect}"</span> <span class="ruby-keyword kw">if</span> <span class="ruby-ivar">@log</span>.<span class="ruby-identifier">debug?</span>
200:
201: <span class="ruby-keyword kw">return</span> <span class="ruby-identifier">buffer</span>
202: <span class="ruby-keyword kw">end</span>
203: <span class="ruby-keyword kw">end</span>
</pre>
</div>
</div>
</div>
<div class="method">
<div class="title">
<a name="M000068"></a><b>set_algorithms</b>( cipher, mac, decompressor )
</div>
<div class="description">
<p>
Set the cipher, mac, and decompressor algorithms to the given values.
</p>
</div>
<div class="sourcecode">
<p class="source-link">[ <a href="javascript:toggleSource('M000068_source')" id="l_M000068_source">show source</a> ]</p>
<div id="M000068_source" class="dyn-source">
<pre>
<span class="ruby-comment cmt"># File lib/net/ssh/transport/packet-stream.rb, line 148</span>
148: <span class="ruby-keyword kw">def</span> <span class="ruby-identifier">set_algorithms</span>( <span class="ruby-identifier">cipher</span>, <span class="ruby-identifier">mac</span>, <span class="ruby-identifier">decompressor</span> )
149: <span class="ruby-keyword kw">super</span>( <span class="ruby-identifier">cipher</span>, <span class="ruby-identifier">mac</span> )
150: <span class="ruby-ivar">@decompressor</span> = <span class="ruby-identifier">decompressor</span>
151: <span class="ruby-keyword kw">end</span>
</pre>
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