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Subject: Re: [PATCH net-next v1 2/9] net: dsa: tag_ar9331: detect IGMP and MLD
 packets
To:     Andrew Lunn <andrew@lunn.ch>,
        Oleksij Rempel <o.rempel@pengutronix.de>
Cc:     Vivien Didelot <vivien.didelot@gmail.com>,
        Florian Fainelli <f.fainelli@gmail.com>,
        Vladimir Oltean <olteanv@gmail.com>,
        "David S. Miller" <davem@davemloft.net>,
        Jakub Kicinski <kuba@kernel.org>,
        Russell King <linux@armlinux.org.uk>,
        Pengutronix Kernel Team <kernel@pengutronix.de>,
        netdev@vger.kernel.org, linux-kernel@vger.kernel.org,
        linux-mips@vger.kernel.org
References: <20210403114848.30528-1-o.rempel@pengutronix.de>
 <20210403114848.30528-3-o.rempel@pengutronix.de> <YGiAjngOfDVWz/D7@lunn.ch>
From:   Oleksij Rempel <linux@rempel-privat.de>
Message-ID: <f4856601-4219-09c7-2933-2161afd03abe@rempel-privat.de>
Date:   Sat, 3 Apr 2021 19:14:56 +0200
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Am 03.04.21 um 16:49 schrieb Andrew Lunn:
>> @@ -31,6 +96,13 @@ static struct sk_buff *ar9331_tag_xmit(struct sk_buf=
f *skb,
>>  	__le16 *phdr;
>>  	u16 hdr;
>>
>> +	if (dp->stp_state =3D=3D BR_STATE_BLOCKING) {
>> +		/* TODO: should we reflect it in the stats? */
>> +		netdev_warn_once(dev, "%s:%i dropping blocking packet\n",
>> +				 __func__, __LINE__);
>> +		return NULL;
>> +	}
>> +
>>  	phdr =3D skb_push(skb, AR9331_HDR_LEN);
>>
>>  	hdr =3D FIELD_PREP(AR9331_HDR_VERSION_MASK, AR9331_HDR_VERSION);
>
> Hi Oleksij
>
> This change does not seem to fit with what this patch is doing.

done

> I also think it is wrong. You still need BPDU to pass through a
> blocked port, otherwise spanning tree protocol will be unstable.

We need a better filter, otherwise, in case of software based STP, we are =
leaking packages on
blocked port. For example DHCP do trigger lots of spam in the kernel log.

I'll drop STP patch for now, it will be better to make a generic soft STP =
for all switches without
HW offloading. For example ksz9477 is doing SW based STP in similar way.

=2D-
Regards,
Oleksij