Greg KH <gregkh@xxxxxxxxxxxxxxxxxxx> writes:
On Wed, Sep 28, 2022 at 06:20:28PM +0200, Joash Naidoo wrote:
> But also, shouldn't you just be using the ip_hdr() call
> instead of doing
> the crazy cast above?
I would need to investigate and test first before commenting.
If a change
had to be made, I believe it will go in a separate patch?
Yes, that would be good to do as a patch series.
thanks,
greg k-h
Hi all
I want to investigate Greg's suggestion to replace the original
code's iph cast with ip_hdr(). Looking into the ip_hdr() function
it seems it effectively casts skb->head + skb->network_header
property (See [1, 2]) whereas the original code casts skb->data +
ETH_HLEN [3]. My goal was to use printk statements to see if
they're equivalent before making any actual changes.
Could anyone advise to a high level action which will trigger the
dhcp_flag_bcast() function, as seen in my patch. I have limited
knowledge but I would imagine this function is called when the
device broadcasts an IP address request from the DHCP server. I am
using dhcpcd as a client and I have tried to manually trigger this
action by deleting device's lease file and restarting dhcpcd.
Among trying other basic things, I have been unsuccessful at
triggering this function.
Looking further up the code at the rtw_xmit() function [4], I
learnt the following. Perhaps understanding br_port may also help
me.
void *br_port = NULL;
br_port = rcu_dereference(padapter->pnetdev->rx_handler_data);
// <-- this returns 0x00
if (br_port && check_fwstate(pmlmepriv, WIFI_STATION_STATE |
WIFI_ADHOC_STATE)) { // <-- false because of br_port, second
condition is true
res = rtw_br_client_tx(padapter, ppkt); // <-- later calls
the dhcp_flag_bcast() See [5]
if (res == -1) {
rtw_free_xmitframe(pxmitpriv, pxmitframe);
return -1;
}
}
[1]
https://elixir.bootlin.com/linux/v6.0-rc5/source/include/linux/ip.h#L19
[2]
https://elixir.bootlin.com/linux/v6.0-rc5/source/include/linux/skbuff.h#L2819
[3]
https://elixir.bootlin.com/linux/v6.0-rc5/source/drivers/staging/r8188eu/core/rtw_br_ext.c#L611
[4]
https://elixir.bootlin.com/linux/v6.0-rc5/source/drivers/staging/r8188eu/core/rtw_xmit.c#L1670
[5]
https://elixir.bootlin.com/linux/v6.0-rc5/source/drivers/staging/r8188eu/core/rtw_xmit.c#L1598
Thank you all for your time and support.
Kind regards,
Joash
