Object
Encapsulates state information about one end of an SSH connection. Such state includes the packet sequence number, the algorithms in use, how many packets and blocks have been processed since the last reset, and so forth. This class will never be instantiated directly, but is used as part of the internal state of the PacketStream module.
The maximum number of blocks that this endpoint wants to process before needing a rekey.
The maximum number of packets that this endpoint wants to process before needing a rekey.
Creates a new state object, belonging to the given socket. Initializes the algorithms to “none”.
# File lib/net/ssh/transport/state.rb, line 57 def initialize(socket, role) @socket = socket @role = role @sequence_number = @packets = @blocks = 0 @cipher = CipherFactory.get("none") @block_size = 8 @hmac = HMAC.get("none") @compression = nil @compressor = @decompressor = nil @next_iv = "" end
Closes any the compressor and/or decompressor objects that have been instantiated.
# File lib/net/ssh/transport/state.rb, line 167 def cleanup if @compressor @compressor.finish if !@compressor.finished? @compressor.close end if @decompressor # we call reset here so that we don't get warnings when we try to # close the decompressor @decompressor.reset @decompressor.close end @compressor = @decompressor = nil end
Compresses the data. If no compression is in effect, this will just return the data unmodified, otherwise it uses compressor to compress the data.
# File lib/net/ssh/transport/state.rb, line 120 def compress(data) data = data.to_s return data unless compression? compressor.deflate(data, Zlib::SYNC_FLUSH) end
Returns true if data compression/decompression is enabled. This will return true if :standard compression is selected, or if :delayed compression is selected and the :authenticated hint has been received by the socket.
# File lib/net/ssh/transport/state.rb, line 114 def compression? compression == :standard || (compression == :delayed && socket.hints[:authenticated]) end
The compressor object to use when compressing data. This takes into account the desired compression level.
# File lib/net/ssh/transport/state.rb, line 101 def compressor @compressor ||= Zlib::Deflate.new(compression_level || Zlib::DEFAULT_COMPRESSION) end
Deompresses the data. If no compression is in effect, this will just return the data unmodified, otherwise it uses decompressor to decompress the data.
# File lib/net/ssh/transport/state.rb, line 128 def decompress(data) data = data.to_s return data unless compression? decompressor.inflate(data) end
The decompressor object to use when decompressing data.
# File lib/net/ssh/transport/state.rb, line 106 def decompressor @decompressor ||= Zlib::Inflate.new(nil) end
# File lib/net/ssh/transport/state.rb, line 84 def final_cipher result = cipher.final update_next_iv(role == :client ? result : "", true) return result end
Increments the counters. The sequence number is incremented (and remapped so it always fits in a 32-bit integer). The number of packets and blocks are also incremented.
# File lib/net/ssh/transport/state.rb, line 93 def increment(packet_length) @sequence_number = (@sequence_number + 1) & 0xFFFFFFFF @packets += 1 @blocks += (packet_length + 4) / @block_size end
Returns true if the number of packets processed exceeds the maximum number of packets, or if the number of blocks processed exceeds the maximum number of blocks.
# File lib/net/ssh/transport/state.rb, line 186 def needs_rekey? max_packets && packets > max_packets || max_blocks && blocks > max_blocks end
Resets the counters on the state object, but leaves the sequence_number unchanged. It also sets defaults for and recomputes the max_packets and max_blocks values.
# File lib/net/ssh/transport/state.rb, line 137 def reset! @packets = @blocks = 0 @max_packets ||= 1 << 31 @block_size = cipher.name == "RC4" ? 8 : cipher.block_size if max_blocks.nil? # cargo-culted from openssh. the idea is that "the 2^(blocksize*2) # limit is too expensive for 3DES, blowfish, etc., so enforce a 1GB # limit for small blocksizes." if @block_size >= 16 @max_blocks = 1 << (@block_size * 2) else @max_blocks = (1 << 30) / @block_size end # if a limit on the # of bytes has been given, convert that into a # minimum number of blocks processed. if rekey_limit @max_blocks = [@max_blocks, rekey_limit / @block_size].min end end cleanup end
Generated with the Darkfish Rdoc Generator 2.