102 lines
4.4 KiB
Ruby
102 lines
4.4 KiB
Ruby
require 'net/ssh/buffer'
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require 'net/ssh/transport/constants'
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require 'net/ssh/authentication/constants'
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require 'net/ssh/connection/constants'
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module Net; module SSH
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# A specialization of Buffer that knows the format of certain common
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# packet types. It auto-parses those packet types, and allows them to
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# be accessed via the #[] accessor.
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#
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# data = some_channel_request_packet
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# packet = Net::SSH::Packet.new(data)
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#
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# p packet.type #-> 98 (CHANNEL_REQUEST)
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# p packet[:request]
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# p packet[:want_reply]
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#
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# This is used exclusively internally by Net::SSH, and unless you're doing
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# protocol-level manipulation or are extending Net::SSH in some way, you'll
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# never need to use this class directly.
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class Packet < Buffer
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@@types = {}
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# Register a new packet type that should be recognized and auto-parsed by
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# Net::SSH::Packet. Note that any packet type that is not preregistered
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# will not be autoparsed.
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#
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# The +pairs+ parameter must be either empty, or an array of two-element
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# tuples, where the first element of each tuple is the name of the field,
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# and the second is the type.
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#
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# register DISCONNECT, [:reason_code, :long], [:description, :string], [:language, :string]
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def self.register(type, *pairs)
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@@types[type] = pairs
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end
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include Transport::Constants, Authentication::Constants, Connection::Constants
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#--
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# These are the recognized packet types. All other packet types will be
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# accepted, but not auto-parsed, requiring the client to parse the
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# fields using the methods provided by Net::SSH::Buffer.
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#++
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register DISCONNECT, [:reason_code, :long], [:description, :string], [:language, :string]
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register IGNORE, [:data, :string]
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register UNIMPLEMENTED, [:number, :long]
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register DEBUG, [:always_display, :bool], [:message, :string], [:language, :string]
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register SERVICE_ACCEPT, [:service_name, :string]
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register USERAUTH_BANNER, [:message, :string], [:language, :string]
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register USERAUTH_FAILURE, [:authentications, :string], [:partial_success, :bool]
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register GLOBAL_REQUEST, [:request_type, :string], [:want_reply, :bool], [:request_data, :buffer]
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register CHANNEL_OPEN, [:channel_type, :string], [:remote_id, :long], [:window_size, :long], [:packet_size, :long]
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register CHANNEL_OPEN_CONFIRMATION, [:local_id, :long], [:remote_id, :long], [:window_size, :long], [:packet_size, :long]
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register CHANNEL_OPEN_FAILURE, [:local_id, :long], [:reason_code, :long], [:description, :string], [:language, :string]
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register CHANNEL_WINDOW_ADJUST, [:local_id, :long], [:extra_bytes, :long]
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register CHANNEL_DATA, [:local_id, :long], [:data, :string]
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register CHANNEL_EXTENDED_DATA, [:local_id, :long], [:data_type, :long], [:data, :string]
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register CHANNEL_EOF, [:local_id, :long]
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register CHANNEL_CLOSE, [:local_id, :long]
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register CHANNEL_REQUEST, [:local_id, :long], [:request, :string], [:want_reply, :bool], [:request_data, :buffer]
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register CHANNEL_SUCCESS, [:local_id, :long]
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register CHANNEL_FAILURE, [:local_id, :long]
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# The (integer) type of this packet.
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attr_reader :type
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# Create a new packet from the given payload. This will automatically
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# parse the packet if it is one that has been previously registered with
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# Packet.register; otherwise, the packet will need to be manually parsed
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# using the methods provided in the Net::SSH::Buffer superclass.
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def initialize(payload)
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@named_elements = {}
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super
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@type = read_byte
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instantiate!
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end
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# Access one of the auto-parsed fields by name. Raises an error if no
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# element by the given name exists.
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def [](name)
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name = name.to_sym
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raise ArgumentError, "no such element #{name}" unless @named_elements.key?(name)
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@named_elements[name]
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end
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private
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# Parse the packet's contents and assign the named elements, as described
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# by the registered format for the packet.
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def instantiate!
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(@@types[type] || []).each do |name, datatype|
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@named_elements[name.to_sym] = if datatype == :buffer
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remainder_as_buffer
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else
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send("read_#{datatype}")
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end
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end
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end
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end
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end; end |