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Subject: Re: [PATCH] rsi: Fix TX EAPOL packet handling against iwlwifi AP
To:     Marek Vasut <marex@denx.de>, netdev@vger.kernel.org
Cc:     Angus Ainslie <angus@akkea.ca>,
        "David S . Miller" <davem@davemloft.net>,
        Jakub Kicinski <kuba@kernel.org>,
        Kalle Valo <kvalo@codeaurora.org>,
        Lee Jones <lee.jones@linaro.org>,
        Martin Kepplinger <martink@posteo.de>,
        Sebastian Krzyszkowiak <sebastian.krzyszkowiak@puri.sm>,
        Siva Rebbagondla <siva8118@gmail.com>,
        linux-wireless@vger.kernel.org
References: <20201015111616.429220-1-marex@denx.de>
From:   Martin Fuzzey <martin.fuzzey@flowbird.group>
Message-ID: <ba9013a8-38e4-f1ee-05a7-c3cf668bf449@flowbird.group>
Date:   Thu, 27 May 2021 18:52:32 +0200
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Hi Marek,

I've just run into the same problem (on -5.4) and found your (now 
merged) patch


On 15/10/2020 13:16, Marek Vasut wrote:
> In case RSI9116 SDIO WiFi operates in STA mode against Intel 9260 in AP mode,
> the association fails. The former is using wpa_supplicant during association,
> the later is set up using hostapd:
>
> iwl$ cat hostapd.conf
> interface=wlp1s0
> ssid=test
> country_code=DE
> hw_mode=g
> channel=1
> wpa=2
> wpa_passphrase=test
> wpa_key_mgmt=WPA-PSK
> iwl$ hostapd -d hostapd.conf
>
> rsi$ wpa_supplicant -i wlan0 -c <(wpa_passphrase test test)
>
> The problem is that the TX EAPOL data descriptor RSI_DESC_REQUIRE_CFM_TO_HOST
> flag and extended descriptor EAPOL4_CONFIRM frame type are not set in case the
> AP is iwlwifi, because in that case the TX EAPOL packet is 2 bytes shorter.
>
> The downstream vendor driver has this change in place already [1], however
> there is no explanation for it, neither is there any commit history from which
> such explanation could be obtained.
>

I get this using 2 RSI9116 s, for both AP and STA using hostapd.
Comparing packet captures in the working and non working (without your 
patch) case shows that
the working case has a 802.11 QOS header whereas the non working case 
does not, hence the 2 byte difference.
The size of the EAPOL data is the same, it's the previous header that 
causes the problem...

This whole use the message size to determine the messages to ACK seems 
very fragile...

Regards,


Martin