70 lines
2.1 KiB
Ruby
70 lines
2.1 KiB
Ruby
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require 'net/ssh/errors'
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require 'net/ssh/loggable'
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require 'net/ssh/version'
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module Net; module SSH; module Transport
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# Negotiates the SSH protocol version and trades information about server
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# and client. This is never used directly--it is always called by the
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# transport layer as part of the initialization process of the transport
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# layer.
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#
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# Note that this class also encapsulates the negotiated version, and acts as
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# the authoritative reference for any queries regarding the version in effect.
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class ServerVersion
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include Loggable
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# The SSH version string as reported by Net::SSH
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PROTO_VERSION = "SSH-2.0-Ruby/Net::SSH_#{Net::SSH::Version::CURRENT} #{RUBY_PLATFORM}"
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# Any header text sent by the server prior to sending the version.
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attr_reader :header
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# The version string reported by the server.
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attr_reader :version
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# Instantiates a new ServerVersion and immediately (and synchronously)
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# negotiates the SSH protocol in effect, using the given socket.
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def initialize(socket, logger)
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@header = ""
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@version = nil
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@logger = logger
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negotiate!(socket)
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end
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private
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# Negotiates the SSH protocol to use, via the given socket. If the server
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# reports an incompatible SSH version (e.g., SSH1), this will raise an
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# exception.
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def negotiate!(socket)
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info { "negotiating protocol version" }
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loop do
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@version = ""
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loop do
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b = socket.recv(1)
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if b.nil?
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raise Net::SSH::Disconnect, "connection closed by remote host"
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end
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@version << b
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break if b == "\n"
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end
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break if @version.match(/^SSH-/)
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@header << @version
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end
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@version.chomp!
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debug { "remote is `#{@version}'" }
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unless @version.match(/^SSH-(1\.99|2\.0)-/)
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raise Net::SSH::Exception, "incompatible SSH version `#{@version}'"
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end
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debug { "local is `#{PROTO_VERSION}'" }
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socket.write "#{PROTO_VERSION}\r\n"
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socket.flush
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end
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end
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end; end; end
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