Prevent multiple instances of the client on the same machine

[Vito Botta]

hello pals

does anyone have any suggestion on how to prevent multiple instances
of a BrB client on the same machine?

cheers
Vito

[Guillaume Luccisano]

Hi, why do you mean exactly, that your server will accept only one client per host ?

2011/5/23 Vito Botta <ma...@vitobotta.com>

[Vito Botta]

Hi Guillaume,

Yes, correct. I think I figured it out. On the server, when a client connects and a tunnel is initialised, I can find out the client's ip and port through EventMachine, and then use this information to see if a client is already connected from the same IP address and, if this is the case, I call close_connection on the tunnel so the other instance on the client knows it has to shut down.

So this seems to be working well, plus it gave me another idea: since I can get the IP address of the client easily, I can also use then drb's acl to implement some sort of app-firewall :)

For now I am just monkey patching to see how this works but I will add to some other changes I mentioned earlier and send a pull request:

class BrB::Tunnel::Handler

  attr_reader :ip_address, :port

  alias_method :post_init_without_client_ip_and_port, :post_init

  def post_init

    @port, @ip_address = Socket.unpack_sockaddr_in(get_peername) 

    post_init_without_client_ip_and_port

  end

end

then to access and use this information:

    BrB::Service.start_service(@settings) do |event, client| 

      if event == :register

        if allowed_client? client

          if already_connected? client

            client.close_connection

          else

            logger.info  "Client connected on #{client.ip_address}:#{client.port}"

          end

        else

          logger.warn  "Blocked connection from unauthorised client on #{client.ip_address}:#{client.port}"

        end

      else 

     # do something else

      end

    end

Cheers

Vito