Class Net::SSH::Transport::State
In: lib/net/ssh/transport/state.rb
lib/net/ssh/transport/state.rb
Parent: 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.

Methods

Attributes

blocks  [R]  The number of data blocks processed since the last call to reset!
blocks  [R]  The number of data blocks processed since the last call to reset!
cipher  [R]  The cipher algorithm in use for this socket endpoint.
cipher  [R]  The cipher algorithm in use for this socket endpoint.
compression  [R]  The compression algorithm in use for this endpoint.
compression  [R]  The compression algorithm in use for this endpoint.
compression_level  [R]  The compression level to use when compressing data (or nil, for the default).
compression_level  [R]  The compression level to use when compressing data (or nil, for the default).
hmac  [R]  The hmac algorithm in use for this endpoint.
hmac  [R]  The hmac algorithm in use for this endpoint.
max_blocks  [RW]  The maximum number of blocks that this endpoint wants to process before needing a rekey.
max_blocks  [RW]  The maximum number of blocks that this endpoint wants to process before needing a rekey.
max_packets  [RW]  The maximum number of packets that this endpoint wants to process before needing a rekey.
max_packets  [RW]  The maximum number of packets that this endpoint wants to process before needing a rekey.
packets  [R]  The number of packets processed since the last call to reset!
packets  [R]  The number of packets processed since the last call to reset!
rekey_limit  [RW]  The user-specified maximum number of bytes that this endpoint ought to process before needing a rekey.
rekey_limit  [RW]  The user-specified maximum number of bytes that this endpoint ought to process before needing a rekey.
sequence_number  [R]  The next packet sequence number for this socket endpoint.
sequence_number  [R]  The next packet sequence number for this socket endpoint.
socket  [R]  The socket object that owns this state object.
socket  [R]  The socket object that owns this state object.

Public Class methods

Creates a new state object, belonging to the given socket. Initializes the algorithms to "none".

[Source]

    # File lib/net/ssh/transport/state.rb, line 51
51:     def initialize(socket)
52:       @socket = socket
53:       @sequence_number = @packets = @blocks = 0
54:       @cipher = CipherFactory.get("none")
55:       @hmac = HMAC.get("none")
56:       @compression = nil
57:       @compressor = @decompressor = nil
58:     end

Creates a new state object, belonging to the given socket. Initializes the algorithms to "none".

[Source]

    # File lib/net/ssh/transport/state.rb, line 51
51:     def initialize(socket)
52:       @socket = socket
53:       @sequence_number = @packets = @blocks = 0
54:       @cipher = CipherFactory.get("none")
55:       @hmac = HMAC.get("none")
56:       @compression = nil
57:       @compressor = @decompressor = nil
58:     end

Public Instance methods

Closes any the compressor and/or decompressor objects that have been instantiated.

[Source]

     # File lib/net/ssh/transport/state.rb, line 145
145:     def cleanup
146:       if @compressor
147:         @compressor.finish if !@compressor.finished?
148:         @compressor.close
149:       end
150: 
151:       if @decompressor
152:         # we call reset here so that we don't get warnings when we try to
153:         # close the decompressor
154:         @decompressor.reset
155:         @decompressor.close
156:       end
157: 
158:       @compressor = @decompressor = nil
159:     end

Closes any the compressor and/or decompressor objects that have been instantiated.

[Source]

     # File lib/net/ssh/transport/state.rb, line 145
145:     def cleanup
146:       if @compressor
147:         @compressor.finish if !@compressor.finished?
148:         @compressor.close
149:       end
150: 
151:       if @decompressor
152:         # we call reset here so that we don't get warnings when we try to
153:         # close the decompressor
154:         @decompressor.reset
155:         @decompressor.close
156:       end
157: 
158:       @compressor = @decompressor = nil
159:     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.

[Source]

     # File lib/net/ssh/transport/state.rb, line 99
 99:     def compress(data)
100:       data = data.to_s
101:       return data unless compression?
102:       compressor.deflate(data, Zlib::SYNC_FLUSH)
103:     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.

[Source]

     # File lib/net/ssh/transport/state.rb, line 99
 99:     def compress(data)
100:       data = data.to_s
101:       return data unless compression?
102:       compressor.deflate(data, Zlib::SYNC_FLUSH)
103:     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.

[Source]

    # File lib/net/ssh/transport/state.rb, line 93
93:     def compression?
94:       compression == :standard || (compression == :delayed && socket.hints[:authenticated])
95:     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.

[Source]

    # File lib/net/ssh/transport/state.rb, line 93
93:     def compression?
94:       compression == :standard || (compression == :delayed && socket.hints[:authenticated])
95:     end

The compressor object to use when compressing data. This takes into account the desired compression level.

[Source]

    # File lib/net/ssh/transport/state.rb, line 80
80:     def compressor
81:       @compressor ||= Zlib::Deflate.new(compression_level || Zlib::DEFAULT_COMPRESSION)
82:     end

The compressor object to use when compressing data. This takes into account the desired compression level.

[Source]

    # File lib/net/ssh/transport/state.rb, line 80
80:     def compressor
81:       @compressor ||= Zlib::Deflate.new(compression_level || Zlib::DEFAULT_COMPRESSION)
82:     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.

[Source]

     # File lib/net/ssh/transport/state.rb, line 107
107:     def decompress(data)
108:       data = data.to_s
109:       return data unless compression?
110:       decompressor.inflate(data)
111:     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.

[Source]

     # File lib/net/ssh/transport/state.rb, line 107
107:     def decompress(data)
108:       data = data.to_s
109:       return data unless compression?
110:       decompressor.inflate(data)
111:     end

The decompressor object to use when decompressing data.

[Source]

    # File lib/net/ssh/transport/state.rb, line 85
85:     def decompressor
86:       @decompressor ||= Zlib::Inflate.new(nil)
87:     end

The decompressor object to use when decompressing data.

[Source]

    # File lib/net/ssh/transport/state.rb, line 85
85:     def decompressor
86:       @decompressor ||= Zlib::Inflate.new(nil)
87:     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.

[Source]

    # File lib/net/ssh/transport/state.rb, line 72
72:     def increment(packet_length)
73:       @sequence_number = (@sequence_number + 1) & 0xFFFFFFFF
74:       @packets += 1
75:       @blocks += (packet_length + 4) / cipher.block_size
76:     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.

[Source]

    # File lib/net/ssh/transport/state.rb, line 72
72:     def increment(packet_length)
73:       @sequence_number = (@sequence_number + 1) & 0xFFFFFFFF
74:       @packets += 1
75:       @blocks += (packet_length + 4) / cipher.block_size
76:     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.

[Source]

     # File lib/net/ssh/transport/state.rb, line 164
164:     def needs_rekey?
165:       max_packets && packets > max_packets ||
166:       max_blocks && blocks > max_blocks
167:     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.

[Source]

     # File lib/net/ssh/transport/state.rb, line 164
164:     def needs_rekey?
165:       max_packets && packets > max_packets ||
166:       max_blocks && blocks > max_blocks
167:     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.

[Source]

     # File lib/net/ssh/transport/state.rb, line 116
116:     def reset!
117:       @packets = @blocks = 0
118: 
119:       @max_packets ||= 1 << 31
120: 
121:       if max_blocks.nil?
122:         # cargo-culted from openssh. the idea is that "the 2^(blocksize*2)
123:         # limit is too expensive for 3DES, blowfish, etc., so enforce a 1GB
124:         # limit for small blocksizes."
125: 
126:         if cipher.block_size >= 16
127:           @max_blocks = 1 << (cipher.block_size * 2)
128:         else
129:           @max_blocks = (1 << 30) / cipher.block_size
130:         end
131: 
132:         # if a limit on the # of bytes has been given, convert that into a
133:         # minimum number of blocks processed.
134: 
135:         if rekey_limit
136:           @max_blocks = [@max_blocks, rekey_limit / cipher.block_size].min
137:         end
138:       end
139: 
140:       cleanup
141:     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.

[Source]

     # File lib/net/ssh/transport/state.rb, line 116
116:     def reset!
117:       @packets = @blocks = 0
118: 
119:       @max_packets ||= 1 << 31
120: 
121:       if max_blocks.nil?
122:         # cargo-culted from openssh. the idea is that "the 2^(blocksize*2)
123:         # limit is too expensive for 3DES, blowfish, etc., so enforce a 1GB
124:         # limit for small blocksizes."
125: 
126:         if cipher.block_size >= 16
127:           @max_blocks = 1 << (cipher.block_size * 2)
128:         else
129:           @max_blocks = (1 << 30) / cipher.block_size
130:         end
131: 
132:         # if a limit on the # of bytes has been given, convert that into a
133:         # minimum number of blocks processed.
134: 
135:         if rekey_limit
136:           @max_blocks = [@max_blocks, rekey_limit / cipher.block_size].min
137:         end
138:       end
139: 
140:       cleanup
141:     end

A convenience method for quickly setting multiple values in a single command.

[Source]

    # File lib/net/ssh/transport/state.rb, line 62
62:     def set(values)
63:       values.each do |key, value|
64:         instance_variable_set("@#{key}", value)
65:       end
66:       reset!
67:     end

A convenience method for quickly setting multiple values in a single command.

[Source]

    # File lib/net/ssh/transport/state.rb, line 62
62:     def set(values)
63:       values.each do |key, value|
64:         instance_variable_set("@#{key}", value)
65:       end
66:       reset!
67:     end

[Validate]