[Twisted-Python] twisted linux netfilter_log protocol

[David Stainton]

Right. I gave my class one of these: implements(interfaces.IPushProducer,
interfaces.IReadDescriptor)
Which means that I can easily write a class that implements IConsumer
to do something with the packets.

https://github.com/david415/hushVPN/blob/master/nflog_reader.py

This is basically a packet sniffer which receives packets based on iptables
rules.

After that I wrote proxy consumer/producers too; classes that implement
both IConsumer and IPushProducer;
this allows me to transform the packets before sending them to a transport.

I was inspired by this doc:
http://twistedmatrix.com/documents/12.2.0/core/howto/producers.html

So far I really love Twisted!


On Wed, Oct 2, 2013 at 3:14 AM, Phil Mayers <p.mayers at imperial.ac.uk> wrote:

> On 02/10/13 09:25, David Stainton wrote:
>
>>
>> In examples of Twisted UDP clients they all do this:
>>
>> reactor.listenUDP(3000,**MyProtocol())
>>
>> What would I do instead?
>> reactor.addReader makes sense to me since what I have is a file
>> descriptor,
>> and the reactor loop and use select or epoll find out when there is data
>> to read...
>> and call our doRead() method of the Reader.
>>
>> I don't know about implementing this as a Protocol because I do not have
>> any
>> equivalent to ReactorUDP. ReactorUDP's listenUDP returns a ListeningPort.
>> And I'm not sure how a Transport is related to my Reader... but it seems
>> to me
>> that there is some abstraction which sets callbacks for io and also
>> calls buildProtocol...
>>
>
> Sorry, maybe I was unclear: you were asking about protocols, so I was
> merely pointing out that *if* you were to use a protocol, you should copy
> the approach DatagramProtocol and udp.Port take.
>
> However as I noted, it *might not* make sense to do this, if there's only
> ever going to be one socket listening on this "thing", your current
> approach might be fine.
>
>
>  If I am going to be using a Twisted Service to drop privileges after
>> gaining access to the fd...
>> How would I do this? Would I have startService() instantiate a Protocol
>> instance?
>>
>
> As above, it depends. If you're using Protocol instances, then yes. If
> not, then no.
>
> Services are just things which start and stop; they may or may not use
> objects implementing the transport/factory/protocol pattern.
>
>
>
>> I don't know about the nflog file descriptor...
>> but the nflog generator interface is non-blocking if used like this:
>>
>
> Ok. Weird API, but if it works...
>
>
>  My nflog reader seems to work great.
>>
>
> If it works for you, and you're using documented Twisted interfaces, then
> there's probably no need to fiddle with it.
>
>
> ______________________________**_________________
> Twisted-Python mailing list
> Twisted-Python at twistedmatrix.**com <Twisted-Python at twistedmatrix.com>
> http://twistedmatrix.com/cgi-**bin/mailman/listinfo/twisted-**python<http://twistedmatrix.com/cgi-bin/mailman/listinfo/twisted-python>
>
-------------- next part --------------
An HTML attachment was scrubbed...
URL: <http://twistedmatrix.com/pipermail/twisted-python/attachments/20131005/e93d54f4/attachment.html>