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From:   Kalle Valo <kvalo@kernel.org>
To:     Ian Lin <ian.lin@infineon.com>
Cc:     <linux-wireless@vger.kernel.org>,
        <brcm80211-dev-list@broadcom.com>,
        <brcm80211-dev-list@cypress.com>, <franky.lin@broadcom.com>,
        <hante.meuleman@broadcom.com>, <Double.Lo@infineon.com>
Subject: Re: [PATCH v3 4/5] brcmfmac: Update SSID of hidden AP while informing its bss to cfg80211 layer
References: <20220927034138.20463-1-ian.lin@infineon.com>
        <20220927034138.20463-5-ian.lin@infineon.com>
Date:   Wed, 28 Sep 2022 09:38:48 +0300
In-Reply-To: <20220927034138.20463-5-ian.lin@infineon.com> (Ian Lin's message
        of "Mon, 26 Sep 2022 22:41:37 -0500")
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Ian Lin <ian.lin@infineon.com> writes:

> From: Syed Rafiuddeen <syed.rafiuddeen@cypress.com>
>
> cfg80211 layer on DUT STA is disconnecting ongoing connection attempt after
> receiving association response, because cfg80211 layer does not have valid
> AP bss information. On association response event, brcmfmac communicates
> the AP bss information to cfg80211 layer, but SSID seem to be empty in AP
> bss information, and cfg80211 layer prints kernel warning and then
> disconnects the ongoing connection attempt.
>
> SSID is empty in SSID IE, but 'bi->SSID' contains a valid SSID, so
> updating the SSID for hidden AP while informing its bss information
> to cfg80211 layer.
>
> Signed-off-by: Syed Rafiuddeen <syed.rafiuddeen@cypress.com>
> Signed-off-by: Chung-Hsien Hsu <chung-hsien.hsu@infineon.com>
> Signed-off-by: Chi-hsien Lin <chi-hsien.lin@infineon.com>
> Signed-off-by: Ian Lin <ian.lin@infineon.com>
> ---
>  .../net/wireless/broadcom/brcm80211/brcmfmac/cfg80211.c   | 8 ++++++++
>  1 file changed, 8 insertions(+)
>
> diff --git a/drivers/net/wireless/broadcom/brcm80211/brcmfmac/cfg80211.c b/drivers/net/wireless/broadcom/brcm80211/brcmfmac/cfg80211.c
> index 6c37da42e61b..3560afe0ccfe 100644
> --- a/drivers/net/wireless/broadcom/brcm80211/brcmfmac/cfg80211.c
> +++ b/drivers/net/wireless/broadcom/brcm80211/brcmfmac/cfg80211.c
> @@ -3003,6 +3003,7 @@ static s32 brcmf_inform_single_bss(struct brcmf_cfg80211_info *cfg,
>  	u8 *notify_ie;
>  	size_t notify_ielen;
>  	struct cfg80211_inform_bss bss_data = {};
> +	struct brcmf_tlv *ssid;
>  
>  	if (le32_to_cpu(bi->length) > WL_BSS_INFO_MAX) {
>  		bphy_err(drvr, "Bss info is larger than buffer. Discarding\n");
> @@ -3032,6 +3033,13 @@ static s32 brcmf_inform_single_bss(struct brcmf_cfg80211_info *cfg,
>  	notify_ielen = le32_to_cpu(bi->ie_length);
>  	bss_data.signal = (s16)le16_to_cpu(bi->RSSI) * 100;
>  
> +	ssid = (struct brcmf_tlv *)
> +		brcmf_parse_tlvs(notify_ie, notify_ielen, WLAN_EID_SSID);

This still casts away the const. For some reason brcmf_parse_tlvs()
takes a const buffer:

static const struct brcmf_tlv *brcmf_parse_tlvs(const void *buf, int buflen, uint key)

I'm not familiar with brcmfmac internal so I don't know why it does
that, but that means the buffer cannot be modified. If you need to
modify the ssid should you make a copy of it?

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