<html><head><meta http-equiv="Content-Type" content="text/html charset=iso-8859-1"></head><body style="word-wrap: break-word; -webkit-nbsp-mode: space; -webkit-line-break: after-white-space; ">Thanks for the answer!<div><br></div><div>I was hoping to avoid having to put something like AMP in place, because it looked a bit overkill for my case.</div><div>I think I actually found a way :-)</div><div><br></div><div>I guess I can use the same factory to start all my servers. </div><div><div>So I start my sniffer (in a thread) in my ServerFactory and I keep a dictionary of deferred for each line (corresponds to an emitter and a server port).</div><div>It allows me to call the messageToSend method corresponding to the proper server when receiving data.</div><div><br></div><div>Here is a code extract of what I implemented:</div><div><br></div><div><div>class Oldimon(Protocol):</div><div><br></div><div> def __init__(self, factory):</div><div> self.factory = factory</div><div> self.line = None</div><div><br></div><div> def connectionMade(self):</div><div> # Check the server port to get the line</div><div> # associated to this protocol</div><div> port = self.transport.getHost().port</div><div> self.line = LINES_PORT[port]</div><div> # Add the callback for this line</div><div> self.factory.deferred[self.line] = defer.Deferred()</div><div> self.factory.deferred[self.line].addCallback(self.messageToSend)</div></div><div><br></div><div><br></div><div><div>class OldimonFactory(ServerFactory):</div><div><br></div><div> def __init__(self, device, pcap_filter):</div><div> # pcapDataReceived callback is called everytime a message</div><div> # is received</div><div> reactor.callInThread(run_pcap, device, pcap_filter, self.pcapDataReceived)</div><div> # Dict with a deferred for each line</div><div> self.deferred = dict(zip(LINES_PORT.values(), [None] * len(LINES_PORT)))</div><div><br></div><div> def buildProtocol(self, addr):</div><div> return Oldimon(self)</div><div><br></div><div> def pcapDataReceived(self, data, line):</div><div> if self.deferred[line] is not None:</div><div> # Fire the callback for line</div><div> d, self.deferred[line] = self.deferred[line], None</div><div> d.callback(data)</div></div><div><br></div><div>oldimon_factory = OldimonFactory(device, pcap_filter)</div><div>for port in LINES_PORT.keys():</div><div> reactor.listenTCP(port, oldimon_factory)</div><div>reactor.run()</div><div><br></div><div><br><div><div>Le 1 mars 2013 à 15:31, Laurens Van Houtven <_@lvh.cc> a écrit :</div><br class="Apple-interchange-newline"><blockquote type="cite"><div dir="ltr"><div><div>Well, you'd presumably have a connection to each of the servers in the form of a client factory and a protocol instance. Then, every time you get a message, you figure out which protocol instance you want (the one for the appropriate server) and send a message to it. You could do that with self.transport.write, of course, but it would be much easier to just use a ready-made RPC thing.<br>
<br>One such RPC thing is AMP, which comes with Twisted. You can read more about it here:<br><br><a href="http://amp-protocol.net/">http://amp-protocol.net/</a><br><a href="https://twistedmatrix.com/documents/current/core/howto/amp.html">https://twistedmatrix.com/documents/current/core/howto/amp.html</a><br>
<br></div>You will probably end up having a command like HandlePacket or something (presumably you can come up with a more apt domain-specific name), and something close to self.servers[serverFor(packet.origin)].callRemote(HandlePacket, packet.data), or whatever.<br>
<br></div>I realize this is still pretty vague and high level, so feel free to ask more questions about the parts that are unclear :)<br></div><div class="gmail_extra"><br><br><div class="gmail_quote">On Thu, Feb 28, 2013 at 10:59 PM, Benjamin BERTRAND <span dir="ltr"><<a href="mailto:beenje@gmail.com" target="_blank">beenje@gmail.com</a>></span> wrote:<br>
<blockquote class="gmail_quote" style="margin:0 0 0 .8ex;border-left:1px #ccc solid;padding-left:1ex">Hi,<br>
<br>
I have to replace a piece of software that sniffs the traffic on one interface. It gets different messages that are each associated to a specific emitter.<br>
On the same machine, one server is started for each emitter (on a different port).<br>
And the application is just supposed to use the proper server to send the messages captured (to a client on another machine).<br>
<br>
Not sure if it's clear, but basically if I have 2 emitters A and B, I'll start 2 servers (a and b).<br>
My sniffer will get messages A1, A2, B1, B2, B3...<br>
I have to pass messages A1, A2 to server a, that will just send them to the client (if it is connected of course).<br>
And B1, B2, B3 to server b.<br>
I don't need any buffering. If no client is connected, messages captured are just discarded.<br>
<br>
To sniff the network, I want to use pylibpcap or pcapy.<br>
I found this example to make it work with twisted: <a href="http://dound.com/2009/09/integrating-twisted-with-a-pcap-based-python-packet-sniffer/" target="_blank">http://dound.com/2009/09/integrating-twisted-with-a-pcap-based-python-packet-sniffer/</a><br>
<br>
Starting several servers that use the same protocol is not a problem.<br>
But how do I pass the messages captured to the right server?<br>
How do I make the link between the function sniffing the network and the servers?<br>
<br>
Thanks<br>
<br>
Benjamin<br>
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</blockquote></div><br><br clear="all"><br>-- <br><div dir="ltr">cheers<div>lvh</div></div>
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