class Net::SSH::Transport::ServerVersion

def negotiate!(socket, timeout)
  info { "negotiating protocol version" }
  debug { "local is `#{PROTO_VERSION}'" }
  socket.write "#{PROTO_VERSION}\r\n"
  socket.flush
  if timeout && !IO.select([socket], nil, nil, timeout)
    raise Net::SSH::ConnectionTimeout, "timeout during server version negotiating"
  end
  loop do
    @version = ""
    loop do
      begin
        b = socket.readpartial(1)
        raise Net::SSH::Disconnect, "connection closed by remote host" if b.nil?
      rescue EOFError
        raise Net::SSH::Disconnect, "connection closed by remote host"
      end
      @version << b
      break if b == "\n"
    end
    break if @version.match(/^SSH-/)
    @header << @version
  end
  @version.chomp!
  debug { "remote is `#{@version}'" }
  unless @version.match(/^SSH-(1\.99|2\.0)-/)
    raise Net::SSH::Exception, "incompatible SSH version `#{@version}'"
  end
  if timeout && !IO.select(nil, [socket], nil, timeout)
    raise Net::SSH::ConnectionTimeout, "timeout during client version negotiating"
  end
end