Object
The transport layer represents the lowest level of the SSH protocol, and implements basic message exchanging and protocol initialization. It will never be instantiated directly (unless you really know what you’re about), but will instead be created for you automatically when you create a new SSH session via Net::SSH.start.
The standard port for the SSH protocol.
The port number to connect to, as given in the options to the constructor. If no port number was given, this will default to DEFAULT_PORT.
Instantiates a new transport layer abstraction. This will block until the initial key exchange completes, leaving you with a ready-to-use transport session.
# File lib/net/ssh/transport/session.rb, line 56 56: def initialize(host, options={}) 57: self.logger = options[:logger] 58: 59: @host = host 60: @port = options[:port] || DEFAULT_PORT 61: @bind_address = options[:bind_address] || nil 62: @options = options 63: 64: debug { "establishing connection to #{@host}:#{@port}" } 65: factory = options[:proxy] || TCPSocket 66: @socket = timeout(options[:timeout] || 0) { @bind_address.nil? || options[:proxy] ? factory.open(@host, @port) : factory.open(@host,@port,@bind_address) } 67: @socket.extend(PacketStream) 68: @socket.logger = @logger 69: 70: debug { "connection established" } 71: 72: @queue = [] 73: 74: @host_key_verifier = select_host_key_verifier(options[:paranoid]) 75: 76: 77: @server_version = timeout(options[:timeout] || 0) { ServerVersion.new(socket, logger) } 78: 79: @algorithms = Algorithms.new(self, options) 80: wait { algorithms.initialized? } 81: end
Cleans up (see PacketStream#cleanup) and closes the underlying socket.
# File lib/net/ssh/transport/session.rb, line 104 104: def close 105: socket.cleanup 106: socket.close 107: end
Returns true if the underlying socket has been closed.
# File lib/net/ssh/transport/session.rb, line 99 99: def closed? 100: socket.closed? 101: end
Configure’s the packet stream’s client state with the given set of options. This is typically used to define the cipher, compression, and hmac algorithms to use when sending packets to the server.
# File lib/net/ssh/transport/session.rb, line 231 231: def configure_client(options={}) 232: socket.client.set(options) 233: end
Configure’s the packet stream’s server state with the given set of options. This is typically used to define the cipher, compression, and hmac algorithms to use when reading packets from the server.
# File lib/net/ssh/transport/session.rb, line 238 238: def configure_server(options={}) 239: socket.server.set(options) 240: end
Enqueues the given message, such that it will be sent at the earliest opportunity. This does not block, but returns immediately.
# File lib/net/ssh/transport/session.rb, line 224 224: def enqueue_message(message) 225: socket.enqueue_packet(message) 226: end
Sets a new hint for the packet stream, which the packet stream may use to change its behavior. (See PacketStream#hints).
# File lib/net/ssh/transport/session.rb, line 244 244: def hint(which, value=true) 245: socket.hints[which] = value 246: end
Returns the host (and possibly IP address) in a format compatible with SSH known-host files.
# File lib/net/ssh/transport/session.rb, line 85 85: def host_as_string 86: @host_as_string ||= begin 87: string = "#{host}" 88: string = "[#{string}]:#{port}" if port != DEFAULT_PORT 89: if socket.peer_ip != host 90: string2 = socket.peer_ip 91: string2 = "[#{string2}]:#{port}" if port != DEFAULT_PORT 92: string << "," << string2 93: end 94: string 95: end 96: end
Blocks until a new packet is available to be read, and returns that packet. See #.
# File lib/net/ssh/transport/session.rb, line 150 150: def next_message 151: poll_message(:block) 152: end
Returns a hash of information about the peer (remote) side of the socket, including :ip, :port, :host, and :canonized (see #).
# File lib/net/ssh/transport/session.rb, line 144 144: def peer 145: @peer ||= { :ip => socket.peer_ip, :port => @port.to_i, :host => @host, :canonized => host_as_string } 146: end
Tries to read the next packet from the socket. If mode is :nonblock (the default), this will not block and will return nil if there are no packets waiting to be read. Otherwise, this will block until a packet is available. Note that some packet types (DISCONNECT, IGNORE, UNIMPLEMENTED, DEBUG, and KEXINIT) are handled silently by this method, and will never be returned.
If a key-exchange is in process and a disallowed packet type is received, it will be enqueued and otherwise ignored. When a key-exchange is not in process, and consume_queue is true, packets will be first read from the queue before the socket is queried.
# File lib/net/ssh/transport/session.rb, line 165 165: def poll_message(mode=:nonblock, consume_queue=true) 166: loop do 167: if consume_queue && @queue.any? && algorithms.allow?(@queue.first) 168: return @queue.shift 169: end 170: 171: packet = socket.next_packet(mode) 172: return nil if packet.nil? 173: 174: case packet.type 175: when DISCONNECT 176: raise Net::SSH::Disconnect, "disconnected: #{packet[:description]} (#{packet[:reason_code]})" 177: 178: when IGNORE 179: debug { "IGNORE packet recieved: #{packet[:data].inspect}" } 180: 181: when UNIMPLEMENTED 182: lwarn { "UNIMPLEMENTED: #{packet[:number]}" } 183: 184: when DEBUG 185: send(packet[:always_display] ? :fatal : :debug) { packet[:message] } 186: 187: when KEXINIT 188: algorithms.accept_kexinit(packet) 189: 190: else 191: return packet if algorithms.allow?(packet) 192: push(packet) 193: end 194: end 195: end
Adds the given packet to the packet queue. If the queue is non-empty, # will return packets from the queue in the order they were received.
# File lib/net/ssh/transport/session.rb, line 212 212: def push(packet) 213: @queue.push(packet) 214: end
Requests a rekey operation, and blocks until the operation completes. If a rekey is already pending, this returns immediately, having no effect.
# File lib/net/ssh/transport/session.rb, line 127 127: def rekey! 128: if !algorithms.pending? 129: algorithms.rekey! 130: wait { algorithms.initialized? } 131: end 132: end
Returns immediately if a rekey is already in process. Otherwise, if a rekey is needed (as indicated by the socket, see PacketStream#if_needs_rekey?) one is performed, causing this method to block until it completes.
# File lib/net/ssh/transport/session.rb, line 137 137: def rekey_as_needed 138: return if algorithms.pending? 139: socket.if_needs_rekey? { rekey! } 140: end
Sends the given message via the packet stream, blocking until the entire message has been sent.
# File lib/net/ssh/transport/session.rb, line 218 218: def send_message(message) 219: socket.send_packet(message) 220: end
Returns a new service_request packet for the given service name, ready for sending to the server.
# File lib/net/ssh/transport/session.rb, line 120 120: def service_request(service) 121: Net::SSH::Buffer.from(:byte, SERVICE_REQUEST, :string, service) 122: end
Performs a “hard” shutdown of the connection. In general, this should never be done, but it might be necessary (in a rescue clause, for instance, when the connection needs to close but you don’t know the status of the underlying protocol’s state).
# File lib/net/ssh/transport/session.rb, line 113 113: def shutdown! 114: error { "forcing connection closed" } 115: socket.close 116: end
Waits (blocks) until the given block returns true. If no block is given, this just waits long enough to see if there are any pending packets. Any packets read are enqueued (see #).
# File lib/net/ssh/transport/session.rb, line 200 200: def wait 201: loop do 202: break if block_given? && yield 203: message = poll_message(:nonblock, false) 204: push(message) if message 205: break if !block_given? 206: end 207: end
Instantiates a new host-key verification class, based on the value of the parameter. When true or nil, the default Lenient verifier is returned. If it is false, the Null verifier is returned, and if it is :very, the Strict verifier is returned. If the argument happens to respond to :verify, it is returned directly. Otherwise, an exception is raised.
# File lib/net/ssh/transport/session.rb, line 261 261: def select_host_key_verifier(paranoid) 262: case paranoid 263: when true, nil then 264: Net::SSH::Verifiers::Lenient.new 265: when false then 266: Net::SSH::Verifiers::Null.new 267: when :very then 268: Net::SSH::Verifiers::Strict.new 269: else 270: if paranoid.respond_to?(:verify) 271: paranoid 272: else 273: raise ArgumentError, "argument to :paranoid is not valid: #{paranoid.inspect}" 274: end 275: end 276: end
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