Re: [Discuss-gnuradio] Re: accessing packet payload in reception

[Eric Blossom]

On Mon, Apr 16, 2007 at 12:35:29PM -0500, Ben Olsen wrote:
> Following up:
> 
> >(message = *access to the depths of the demodulation blocks and packet
> >queues, giving me the string "desname.sourcename.str(frequency)" *)
> 
> would this be something along the lines of:
> 
> message = fun_graph.rxpath.packet_receiver._watcher.(_rcvd_pktq....)?
> 
> I get a bit lost this deep into it...
> 
> Again, thanks for any assistance
> -Ben Olsen

Hi Ben,

You shouldn't have to grovel around in the bottom of the code.
The "rx_callback" method in benchmark_rx is called with the received
packet.

FWIW, I'd probably pick a different separator than '.' since it's quite
likely to show up in a frequency.   If you're going to send your
parameters as ASCII, I'd consider using chr(0) as the delimiter.

Eric



> 
> On 4/16/07, Ben Olsen <address@hidden> wrote:
> >Hello!
> >
> >I'm trying to implement a scheme in which I have a receiving node
> >accept a frequency to tune to from a sending node, and I would
> >appreciate any advice how to code this.
> >I'm using the /digital/benchmark_xx.py scripts, so in Tx i've used the
> >defined send_pkt function that packs a message to send like this:
> >
> >def send_pkt(payload='', eof=False):
> >   return fun_graph.txpath.send_pkt(payload, eof)
> >
> >....
> >fun_graph = transmit_graph(mods[options.modulation], options)
> >...
> >
> >send_pkt("%s.%s.%s" % (destname, sourcename, str(frequency) )
> >
> >send_pkt(eof=True)
> >
> >Is this a good way to send such a payload? Next I'd like to get the
> >values destname, sourcename, and frequency out of the received packet
> >at the receiving node, but I'm not sure which blocks/functions to call
> >on to access these. What i'll do with the received message is
> >something along the lines of:
> >
> >(message = *access to the depths of the demodulation blocks and packet
> >queues, giving me the string "desname.sourcename.str(frequency)" *)
> >
> >parsed = message.split('.', 3) # to tokenize the message between the '.'
> >
> ># now tune to parsed[2]....
> >
> >I'd appreciate any help very much!
> >
> >Thanks,
> >
> >Ben Olsen