Hi, > On 31 Jul 2015, at 14:10, Jason Matusiak <[email protected]> > wrote: > >> The wifi_tx example GRC comes with a Socket PDU source. > >> Just send UDP packets to the port specified containing a IEEE 802.11 >> packet's amount of data per UDP packet; >> netcat/nc/ncat is sadly no good for this, because it doesn't allow >> specification of packet sizes. > >> You can also use a file source, stream to tagged stream, tagged stream to >> PDU flow graph. > >> To be honest, GNU Radio is kind of lacking a simple "take n items from the >> input stream and generate a PMT pair >> (n, items), send that over your message port" block, which would take >> roughly 10 lines of python to write (and >> not much more C++) -- so you might as well do that. > > This is something I have struggled with as well. A lot of examples I've > seen are for streaming data (which is admittedly probably want most > people are wanting). > > I have been more interested in sending a packet (or a series of packets) > over the air (the end goal being letting someone connect to my UDP > source block and handing me their data they want to send). I have > played with the WiFi block a bit recently and unfortunately was always > using netcat.... > > 1 - Are you saying that the data's packet being handed to the socket PDU > has to be exactly as long as the pdu_length? That is something I think > I must have glossed over.
You can pass data of any size of up to 1500 bytes (minus a bit for headers). > > 2 - I don't believe there is a way to dump just the payload of the > 802.11 packet, right? Basically, if I sent "Hello World" to the Socket > PDU (which means my pdu_length would need to be set to 11, right?), is > there a way to have those 11 characters be passed out a UDP sink on the > receiver end? Right now the only thing I can see to do is to utilize > the Wireshark Connector and dump the pcap output to file, then take info > and extract the payload from there in post-processing. Is that right? The transceiver wraps your payload in some headers that add stuff like MAC address, frame type, and CRC. These are the minimum fields that are required so that a WiFi card actually accepts the frame. There is currently no option to dump raw bytes, but its a trivial modification of the Wireshark block (dump without a PCAP header). If you want to printed bytes as hex-values on the console that should work with the parse block. Or you could use a Debug Message block and print the PDUs coming out of the PHY / MAC, depending on what you want to see. Best, Bastian _______________________________________________ Discuss-gnuradio mailing list [email protected] https://lists.gnu.org/mailman/listinfo/discuss-gnuradio
