ESP8266 Community Forum

- Sat Jan 17, 2015 8:07 pm #7564 After getting everything up and running, I've been playing around with the chip for about a day and loading my own simple programs on it. I'm looking at the 802.11 packet spec and it doesn't look to provide any info on RSSI values, which makes sense. After looking through the documentation, it doesn't seem that there's any way to get this info from a packet gathered via promiscuous mode, in fact it looks like the callback for wifi_set_promiscuous_rx_cb is only supplied with the slice of the packet starting after the packet's preamble and PLCP header, which I'm assuming would probably be encrypted?

I know wireshark can do this sort of thing, so I'm assuming it's possible, but just a matter of writing the software to do it. Is anyone able to give a high level overview of why or why not this is possible?

Cheers!

- Sun Jan 18, 2015 5:50 am #7589 On linux you get RSSI information from the wifi card driver, and often it's not associated with a particular packet, but collected by the hardware and queried from it asynchronously.

- Tue Jan 20, 2015 3:02 pm #7812 The modem certainly has RSSI info on a packet by packet basis gathered from the preamble. It wouldn't be able to demodulate the packet otherwise. The question is whether this value is available to the outside world through an api. As I understand the WiFi protocol does not require RSSI to be advertised on a packet by packet basis.

I would agree that this is a useful feature for wireshark or other sniffing mode type applications.

- Wed Jan 21, 2015 3:02 pm #7889 I guess since it's in the preamble, and the SDK method only returns the data after the PLCP header, I'd need to hack up the SDK to expose that sort of info, and since it's not OSS...that's not really possible/easy?

or is there another way?