From: Jakub Kicinski <kuba@kernel•org>
To: Romain Gantois <romain.gantois@bootlin•com>
Cc: Alexandre Torgue <alexandre.torgue@foss•st.com>,
Jose Abreu <joabreu@synopsys•com>,
"David S. Miller" <davem@davemloft•net>,
Eric Dumazet <edumazet@google•com>,
Paolo Abeni <pabeni@redhat•com>,
Maxime Coquelin <mcoquelin.stm32@gmail•com>,
Miquel Raynal <miquel.raynal@bootlin•com>,
Maxime Chevallier <maxime.chevallier@bootlin•com>,
Sylvain Girard <sylvain.girard@se•com>,
Pascal EBERHARD <pascal.eberhard@se•com>,
Richard Tresidder <rtresidd@electromag•com.au>,
Linus Walleij <linus.walleij@linaro•org>,
Vladimir Oltean <olteanv@gmail•com>, Andrew Lunn <andrew@lunn•ch>,
Thomas Petazzoni <thomas.petazzoni@bootlin•com>,
netdev@vger•kernel.org, linux-stm32@st-md-mailman•stormreply.com,
linux-arm-kernel@lists•infradead.org, stable@vger•kernel.org,
Vladimir Oltean <vladimir.oltean@nxp•com>
Subject: Re: [PATCH net v5] net: stmmac: Prevent DSA tags from breaking COE
Date: Fri, 12 Jan 2024 18:13:27 -0800 [thread overview]
Message-ID: <20240112181327.505b424e@kernel.org> (raw)
In-Reply-To: <20240111-prevent_dsa_tags-v5-1-63e795a4d129@bootlin.com>
On Thu, 11 Jan 2024 15:58:51 +0100 Romain Gantois wrote:
> Some DSA tagging protocols change the EtherType field in the MAC header
> e.g. DSA_TAG_PROTO_(DSA/EDSA/BRCM/MTK/RTL4C_A/SJA1105). On TX these tagged
> frames are ignored by the checksum offload engine and IP header checker of
> some stmmac cores.
>
> On RX, the stmmac driver wrongly assumes that checksums have been computed
> for these tagged packets, and sets CHECKSUM_UNNECESSARY.
>
> Add an additional check in the stmmac TX and RX hotpaths so that COE is
> deactivated for packets with ethertypes that will not trigger the COE and
> IP header checks.
>
> Fixes: 6b2c6e4a938f ("net: stmmac: propagate feature flags to vlan")
> Cc: <stable@vger•kernel.org>
nit: double space
> +/**
> + * stmmac_has_ip_ethertype() - Check if packet has IP ethertype
> + * @skb: socket buffer to check
> + *
> + * Check if a packet has an ethertype that will trigger the IP header checks
> + * and IP/TCP checksum engine of the stmmac core.
> + *
> + * Return: true if the ethertype can trigger the checksum engine, false otherwise
nit: please don't go over 80 chars unless there's a good reason.
we are old school and stick to checkpatch --max-line-length=80 in netdev
> if (csum_insertion &&
> - priv->plat->tx_queues_cfg[queue].coe_unsupported) {
> + (priv->plat->tx_queues_cfg[queue].coe_unsupported ||
> + !stmmac_has_ip_ethertype(skb))) {
nit: minor misalignment here, the '!' should be under 'p'
> if (unlikely(skb_checksum_help(skb)))
> goto dma_map_err;
> csum_insertion = !csum_insertion;
> @@ -4997,7 +5020,7 @@ static void stmmac_dispatch_skb_zc(struct stmmac_priv *priv, u32 queue,
> stmmac_rx_vlan(priv->dev, skb);
> skb->protocol = eth_type_trans(skb, priv->dev);
>
> - if (unlikely(!coe))
> + if (unlikely(!coe) || !stmmac_has_ip_ethertype(skb))
The lack of Rx side COE checking in this driver is kinda crazy.
Looking at enh_desc_coe_rdes0() it seems like RDES0_FRAME_TYPE
may be the indication we need here?
We can dig into it as a follow up but I'm guessing that sending
an IPv6 packet with extension headers will also make the device
skip checksumming, or a UDP packet with csum of 0?
next prev parent reply other threads:[~2024-01-13 2:13 UTC|newest]
Thread overview: 6+ messages / expand[flat|nested] mbox.gz Atom feed top
2024-01-11 14:58 [PATCH net v5] net: stmmac: Prevent DSA tags from breaking COE Romain Gantois
2024-01-13 2:13 ` Jakub Kicinski [this message]
2024-01-16 12:14 ` Romain Gantois
2024-01-16 15:23 ` Jakub Kicinski
2024-01-16 16:18 ` Romain Gantois
2024-01-16 18:36 ` Jakub Kicinski
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