Unable to transmit/inject 802.11 packets using Scapy

Question

I'm trying to transmit a data frame (using scapy in ubuntu 18.04) between my desktop and laptop. I would like the MSDU to just be some raw data and not an upper layer frame. For whatever reason I am unable to detect transmitted packets between the devices.

Both devices are set in monitor mode and are connected to the same frequency/channel. For example, my desktop has wireless interface wlp4s0 which I set up as follows:

sudo ifconfig wlp4s0 down
sudo iwconfig wlp4s0 mode monitor
sudo ifconfig wlp4s0 up
sudo iwconfig wlp4s0 channel n

When I check iw dev or iwconfig I can see that both wireless interfaces are in monitor mode and at the same frequency with a non-zero tx-power.

I have no problems sniffing the channel using scapy with the following code:

sniff(iface = "wlp4s0", prn = output)

Where prn just prints out the summary of any packet.

When I try to transmit I use the following code on one device:

    header = Dot11(
        addr1 = "00:16:ea:12:34:56",
        addr2 = "00:16:ea:12:34:56",
        addr3 = "ff:ff:ff:ff:ff:ff",
        type = 2,
        subtype = 0,
        FCfield = 0)

    data = "testtesttesttest"
    packet = header / data
    sendp(data, iface= "wlp4s0", loop = 1, inter = 0.100)

Despite the transmitting device stating the packet has been transmitted, the other devices cannot see any of the packets while sniffing the channel. Similarly, while using 'ifconfig' the tx_count for the interface is not increasing.

I've tried switching roles on both devices, but have also had no luck.

Any help would be greatly appreciated, thanks!

Answer 1

It seems that you are sending packets to yourself. addr1 is for the receiver. addr2 is for the sender.