Re: Adding non-blocking connect(), pre_loop and post_loop to NSE?

[Patrick Donnelly <batrick () batbytes com>]

On Aug 25, 2014 1:11 PM, "Jacek Wielemborek" <d33tah () gmail com> wrote:
> Hi,
>
> Today I felt like hacking my nmap-nseportscan branch to see how hard
> would it be implement connect scan using NSE scanning. I wanted the code
> layout to mimick the one I worked out while developing nmap-nsock-scan,
> but then I realized that in order to connect()-scan multiple ports at
> once, instead of doing this like this:
>
> do_connect = function(host, port)
>   local sock = nmap.new_socket()
>   local constatus, conerr = sock:connect(host, port)
>   sock:close()
>   --interpret the resuls etc.
> end
>
> action = function(host)
>   local ports = getports(host)
>   for _, port in ipairs(ports) do
>     connect(host, port)
>   end
> end
>
> I would prefer to do it like this:
>
> connected = function(event, userdata)
>   --interpret the resuls etc.
> end
>
> pre_loop = function(host)
>   startTimeoutClock(host)
>   local ports = getports(host)
>   for _, port in ipairs(ports) do
>     schedule_connect(host, port, connected, nil)
>   end
>
> end
>
> post_loop = function(host)
>   finishTimeoutClock(host)
> end
>
> The pre_loop here would just schedule the connections and return
> immediately, leaving the execution of "connected" callback function to
NSE.
> I took a look at the code and realized that it would probably be wiser
> to ask people that know the NSE subsystem better how such a modification
> should look instead of modifying it blindly. I am especially lost on
> running the post_loop part. Could someone take a look at
> nmap-nseportscan branch and see how to fit my concept there?

The way to do this NSE is to spawn worker threads which block normally on
connect:

See http://nmap.org/book/nse-parallelism.html
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