This class implements various port forwarding services for use by Net::SSH clients. The Forward class should never need to be instantiated directly; instead, it should be accessed via the singleton instance returned by Net::SSH::Connection::Session#forward:
ssh.forward.local(1234, "www.capify.org", 80)
The underlying connection service instance that the port-forwarding services employ.
Instantiates a new Forward service instance atop the given connection service session. This will register new channel open handlers to handle the specialized channels that the SSH port forwarding protocols employ.
# File lib/net/ssh/service/forward.rb, line 24 def initialize(session) @session = session self.logger = session.logger @remote_forwarded_ports = {} @local_forwarded_ports = {} @agent_forwarded = false session.on_open_channel('forwarded-tcpip', &method(:forwarded_tcpip)) session.on_open_channel('auth-agent', &method(:auth_agent_channel)) session.on_open_channel('auth-agent@openssh.com', &method(:auth_agent_channel)) end
Returns a list of all active locally forwarded ports. The returned value is an array of arrays, where each element is a two-element tuple consisting of the local port and bind address corresponding to the forwarding port.
# File lib/net/ssh/service/forward.rb, line 110 def active_locals @local_forwarded_ports.keys end
Returns all active forwarded remote ports. The returned value is an array of two-element tuples, where the first element is the port on the remote host and the second is the bind address.
# File lib/net/ssh/service/forward.rb, line 168 def active_remotes @remote_forwarded_ports.keys end
Enables SSH agent forwarding on the given channel. The forwarded agent will remain active even after the channel closes–the channel is only used as the transport for enabling the forwarded connection. You should never need to call this directly–it is called automatically the first time a session channel is opened, when the connection was created with :forward_agent set to true:
Net::SSH.start("remote.host", "me", :forward_agent => true) do |ssh| ssh.open_channel do |ch| # agent will be automatically forwarded by this point end ssh.loop end
# File lib/net/ssh/service/forward.rb, line 185 def agent(channel) return if @agent_forwarded @agent_forwarded = true channel.send_channel_request("auth-agent-req@openssh.com") do |achannel, success| if success debug { "authentication agent forwarding is active" } else achannel.send_channel_request("auth-agent-req") do |a2channel, success2| if success2 debug { "authentication agent forwarding is active" } else error { "could not establish forwarding of authentication agent" } end end end end end
Terminates an active local forwarded port. If no such forwarded port exists, this will raise an exception. Otherwise, the forwarded connection is terminated.
ssh.forward.cancel_local(1234) ssh.forward.cancel_local(1234, "0.0.0.0")
# File lib/net/ssh/service/forward.rb, line 99 def cancel_local(port, bind_address="127.0.0.1") socket = @local_forwarded_ports.delete([port, bind_address]) socket.shutdown rescue nil socket.close rescue nil session.stop_listening_to(socket) end
Requests that a remote forwarded port be cancelled. The remote forwarded port on the remote host, bound to the given address on the remote host, will be terminated, but not immediately. This method returns immediately after queueing the request to be sent to the server. If for some reason the port cannot be cancelled, an exception will be raised (asynchronously).
If you want to know when the connection has been cancelled, it will no longer be present in the active_remotes list. If you want to block until the port is no longer active, you could do something like this:
ssh.forward.cancel_remote(1234, "0.0.0.0") ssh.loop { ssh.forward.active_remotes.include?([1234, "0.0.0.0"]) }
# File lib/net/ssh/service/forward.rb, line 155 def cancel_remote(port, host="127.0.0.1") session.send_global_request("cancel-tcpip-forward", :string, host, :long, port) do |success, response| if success @remote_forwarded_ports.delete([port, host]) else raise Net::SSH::Exception, "could not cancel remote forward request on #{host}:#{port}" end end end
Starts listening for connections on the local host, and forwards them to the specified remote host/port via the SSH connection. This method accepts either three or four arguments. When four arguments are given, they are:
the local address to bind to
the local port to listen on
the remote host to forward connections to
the port on the remote host to connect to
If three arguments are given, it is as if the local bind address is “127.0.0.1”, and the rest are applied as above.
ssh.forward.local(1234, "www.capify.org", 80) ssh.forward.local("0.0.0.0", 1234, "www.capify.org", 80)
# File lib/net/ssh/service/forward.rb, line 51 def local(*args) if args.length < 3 || args.length > 4 raise ArgumentError, "expected 3 or 4 parameters, got #{args.length}" end local_port_type = :long socket = begin if defined?(UNIXServer) and args.first.class == UNIXServer local_port_type = :string args.shift else bind_address = "127.0.0.1" bind_address = args.shift if args.first.is_a?(String) && args.first =~ /\D/ local_port = args.shift.to_i local_port_type = :long TCPServer.new(bind_address, local_port) end end remote_host = args.shift remote_port = args.shift.to_i @local_forwarded_ports[[local_port, bind_address]] = socket session.listen_to(socket) do |server| client = server.accept debug { "received connection on #{socket}" } channel = session.open_channel("direct-tcpip", :string, remote_host, :long, remote_port, :string, bind_address, local_port_type, local_port) do |achannel| achannel.info { "direct channel established" } end prepare_client(client, channel, :local) channel.on_open_failed do |ch, code, description| channel.error { "could not establish direct channel: #{description} (#{code})" } channel[:socket].close end end end
Requests that all connections on the given remote-port be forwarded via the local host to the given port/host. The last argument describes the bind address on the remote host, and defaults to 127.0.0.1.
This method will return immediately, but the port will not actually be forwarded immediately. If the remote server is not able to begin the listener for this request, an exception will be raised asynchronously.
If you want to know when the connection is active, it will show up in the active_remotes list. If you want to block until the port is active, you could do something like this:
ssh.forward.remote(80, "www.google.com", 1234, "0.0.0.0") ssh.loop { !ssh.forward.active_remotes.include?([1234, "0.0.0.0"]) }
# File lib/net/ssh/service/forward.rb, line 128 def remote(port, host, remote_port, remote_host="127.0.0.1") session.send_global_request("tcpip-forward", :string, remote_host, :long, remote_port) do |success, response| if success debug { "remote forward from remote #{remote_host}:#{remote_port} to #{host}:#{port} established" } @remote_forwarded_ports[[remote_port, remote_host]] = Remote.new(host, port) else error { "remote forwarding request failed" } raise Net::SSH::Exception, "remote forwarding request failed" end end end
an alias, for token backwards compatibility with the 1.x API