Re: [Discuss-gnuradio] IEEE802.11 transceiver - problems sending data

[Cristian Rodríguez]

2017-05-18 10:32 GMT-05:00 Bastian Bloessl <address@hidden>:

Hi,

this is a rather complex setup. I would not immediately run SSH, but start with a simple ping (test GNU Radio and the WiFi card as senders). Try to see what works and what goes wrong, for example, ARP (in both directions) or routing.

Hi Bastian.

THanks a lot for your answer.

 

IIRC, the script just sets up ARP in one direction (from the SDR to the WiFi card). You will have to also add the corresponding entry in reverse direction. It’s not in the script since I always used the WiFi card of another PC.

I did that as follows:

 ### config wifi card interface (wlp4s0)

sudo ifconfig wlp4s0 down
sudo ifconfig wlp4s0 mtu 440
sudo ifconfig wlp4s0 up
sudo ifconfig wlp4s0 192.168.123.2

sudo route del -net 192.168.123.0/24
sudo route add -net 192.168.123.0/24 mss 400 dev wlp4s0

sudo tc qdisc del dev wlp4s0 root
sudo tc qdisc add dev wlp4s0 root netem delay 10ms

sudo arp -s 192.168.123.1 12:34:56:78:90:ab -i wlp4s0

Then use Wireshark to monitor GNU Radio (that’s what you might do at the moment) and also the WiFi card. This might help to understand what frames are actually sent, if they are OK (MAC, IP, BSS) and if they are successfully received by the WiFi card and the SDR.

If i do a ping from the interface tap0 to 192.168.123.2 (IP of my wifi card) it doesn't work. The signal is going out of the USRP but the Wifi Card of the computer is not taking it. 

ping -I tap0 192.168.123.2

If i do a ping from the interface wlp4s0 to 192.168.123.1 (IP of USRP B210) it doesn't work. The signal is NOT going out of the Wifi card (i verifed that through wireshark).

ping -I wlp4s0 192.168.123.1

I append the file nic.sh that i modifed.

When i run arp -a and route, the two modules (USRP and Wifi card) appear correctly in each other interface. And in the route, the router for both interfaces is 192.168.123.0.

(Also make sure that an SSH server is actually running.)

It is running.
 

There are a lot of things that can go wrong in this setup. You should try to narrow it down a bit. Once you have a more specific problem, it might be easier to help.

Then, now i have two interfaces in the same computer.

tap0: USRP B210

wlp4s0: Wifi card

I defined in each one an static IP and in TAP0 a MAC. In general, the elements defined in tap0 are too in wlp4s0.

I'm doing a PING at the moment.

On the other hand, Could you please share me the config file that you used for you computer? I've done a lot of different proofs but i don't understand why my wifi card doesn't receive or send anything.. 

Thanks a lot for your help.

Best regards,

Cristian

 

> On 16. May 2017, at 16:57, Cristian Rodríguez <address@hiddencom> wrote:
>
> Hi all.
>
> I'm trying to run the file nic.sh (app for the transceiver flowgraph in gnuradio) as in this youtube video of Bastian, but i can run it at all.
>
> I have:
>       • USRP B210
>       • i7 4710HQ, 12 Gb RAM, USB 3.0.
>       • Ubuntu 16.04.2
> I'm doing
>
> I understand the proof as:
>
> <image.png>
>
> Then i just would have to reconfigure my PC MAC in the nic.sh file and flowgraph, put a channel in the 2GHz band, set 20 Msamples/s and run it.
>
> It is the main part of nic.sh file. I just changed my MAC and assigned the 192.168.123.2 IP. The other is the same of i got in Github.
>
> <image.png>
>
> I did the same in the flowgraph (just in this WIFI MAC block).
>
> <image.png>
>
> Thus. I run the app by the terminal... ./nic.sh.
>
> Later, i open another terminal and type ssh 192.168.123.2, and it doesn't work as in the video. Then i check wireshark and it is that happens. I'm receiving the petition of a TCP port but it for any reason is not working. In this way i can't connect from the USRP B210 to my pc. I think my PC is not answering the petition or something like that.
>
> <image.png>
>
> The MACs are as supposed (i Checked it in wireshark)
> <image.png>

>
> Thanks in advance for the time to read it.
>
> Best regards,
>
> Cristian