I'm currently working on a rewrite of the CC2520 driver (which couples to the rfxlink library/stack) so it is like the CC2420X code in its interface to the upper layers.
Just had a discussion about hw filtering. Currently hw filtering isn't turned on explicitly because we want to pass the packet upward so Snoop can work. So the hooks should be there. I may see how that works later tonight, I'm about to receive my first packet. On Thu, Sep 19, 2013 at 5:32 PM, Johny Mattsson <[email protected]>wrote: > On 19/09/2013, jpam <[email protected]> wrote: > > Because I'm building a NIDS and I need the some node (/watchdogs/) to act > > "promiscuously" and analyze the packets exchanged in their neighborhood. > > For > > that, I need to access the packet as soon as the radio downloads it and > > before it discards if it's not destined to the mote. To the best of my > > knowledge, I should do that in file CC2420XDriverLayerP (as modified in > the > > application PPPSniffer). The packets aren't sent up the stack if the node > > isn't the final destination, are they? > > From memory, and this is hazy since it's been something like two years > since I worked with this stuff, there are two places in the stack > where the address filtering can happen: > > 1) Hardware filtering by the radio, if available & enabled. I was > using the RF212 and this wasn't active then. > > 2) In the radio driver's receive function. > > If you disable these, I believe you should be able to use the IPRaw > interface on the IPStackC to listen in on all of the IP messages, > whether they're for your node or not (as long as they're on the same > PAN; if they're not, there are additional checks in IPDispatchP and > Ieee154PacketLayer that would need to be removed, iirc). > > You might need to do something to the IP forwarding engine to prevent > it from acting as a router in the above scenario (but that's probably > a good idea on an NIDS anyway). > > Hth, > /Johny > -- > Johny Mattsson > Senior Software Engineer > > DiUS Computing Pty. Ltd. > *where ideas are engineered* > _______________________________________________ > Tinyos-help mailing list > [email protected] > https://www.millennium.berkeley.edu/cgi-bin/mailman/listinfo/tinyos-help > -- Eric B. Decker Senior (over 50 :-) Researcher
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