Class: Net::SSH::Service::Forward

Class | Net::SSH::Service::Forward
In: | lib/net/ssh/service/forward.rb
Parent: | Object

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 Connection::Session#forward:

      ssh.forward.local(1234, "www.capify.org", 80)

### Methods

active_locals active_remotes agent cancel_local cancel_remote local new remote remote_to

### Included Modules

Loggable

### Attributes

session | [R] | The underlying connection service instance that the port-forwarding services employ.

### Public Class methods

new(session)

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.

### Public Instance methods

active_locals()

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.

active_remotes()

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.

agent(channel)

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", :forwrd_agent => true) do |ssh|
         ssh.open_channel do |ch|
           # agent will be automatically forwarded by this point
         end
         ssh.loop
       end

cancel_local(port, bind_address="127.0.0.1")

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")

cancel_remote(port, host="127.0.0.1")

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"]) }

local(*args)

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)

remote(port, host, remote_port, remote_host="127.0.0.1")

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"]) }

remote_to(port, host, remote_port, remote_host="127.0.0.1")

Alias for remote

[Validate]