Using nrf5340 with nrf70 on a custom board, using NCS 2.9.0 (and I can't/won't update to 3.2.x as the nrfx4 update breaks all my code)
I want to use the wifi interface to send raw wifi network packets (both in associated and non-associated modes).
I have the nrf70 blob configured to use the bin that is good for both STA and RAW modes:
(in sysbuild.conf SB_CONFIG_WIFI_NRF70_SYSTEM_WITH_RAW_MODES=y and in prj.conf CONFIG_NRF70_RAW_DATA_TX=y)
I have avoided the memory issue I reported here:
nrf70 raw packet sending causes network memory loss from sysheap
by opening and closing the socket every time I want to send my raw packet (instead of keeping it open all the time)
Now when I send my raw packet it works unless:
1/ I just changed the channel (when not in associated mode) : packet silently dropped
I want to send the packet on channels 1, 4 and 11 for example. The channels are in an array and I have a loop, which changes the channel to the next one, then does the sendto().
channel set request:
- the channel change request returns OK every time (ret=0)
- the subsequent sendto of the packet says it was sent ok
But no packets are ever is seen on the air:
Except the very first one ie when it was already on the desired channel). And indeed, if I change the channel array so it is in fact always the same channel (ie instead of {1, 4, 11} I have {4, 4, 4} then it works fine (I see 3 packets all on channel 4)
Any ideas why changing the channel just before sending breaks the send?
PS> If I change the code to switch the channel AFTER the send, and then wait till the next timer pop to send on it (so the channel change happens with a certain delay (3s in my test) before the sendto()), then this works!
2/ my packet wants to have its frame control field equal to 0x0803 (byte swapped on the air), ie data packet, with DS of 3 : packet silently dropped
In the raw frame wifi header (from the raw tx sample) I set:
With this fc, my packet is NEVER sent (there is no error return from the sendto(), but packet is never on the air)
If I use fc=0x4000 (probe request) its fine. fc=0x8000 (beacon frame) its fine. fc=0x0800 (data frame, DS status=00) then its fine too.
Why does the wifi driver silently drop this packet?
Thanks!
FYI: I'm using wireshark with a Netgear A6210 usb wifi stick on Windows 11 to do the radio packet capture (only does 1 channel at a time, but it works in Monitor mode!)
