2018-10-05 07:05:14

by Maxime Chevallier

Subject: [PATCH net v2] net: mvpp2: Extract the correct ethtype from the skb for tx csum offload

When offloading the L3 and L4 csum computation on TX, we need to extract
the l3_proto from the ethtype, independently of the presence of a vlan
tag.

The actual driver uses skb->protocol as-is, resulting in packets with
the wrong L4 checksum being sent when there's a vlan tag in the packet
header and checksum offloading is enabled.

This commit makes use of vlan_protocol_get() to get the correct ethtype
regardless the presence of a vlan tag.

Fixes: 3f518509dedc ("ethernet: Add new driver for Marvell Armada 375 network unit")
Signed-off-by: Maxime Chevallier <[email protected]>
---
V2: Use htons on values that can be swapped at compile-time, following
Yan's comment. Fix the "Fixes" tag and a typo, following Sergei's comment.

drivers/net/ethernet/marvell/mvpp2/mvpp2_main.c | 9 +++++----
1 file changed, 5 insertions(+), 4 deletions(-)

diff --git a/drivers/net/ethernet/marvell/mvpp2/mvpp2_main.c b/drivers/net/ethernet/marvell/mvpp2/mvpp2_main.c
index 38cc01beea79..a74002b43b51 100644
--- a/drivers/net/ethernet/marvell/mvpp2/mvpp2_main.c
+++ b/drivers/net/ethernet/marvell/mvpp2/mvpp2_main.c
@@ -1725,7 +1725,7 @@ static void mvpp2_txq_desc_put(struct mvpp2_tx_queue *txq)
}

/* Set Tx descriptors fields relevant for CSUM calculation */
-static u32 mvpp2_txq_desc_csum(int l3_offs, int l3_proto,
+static u32 mvpp2_txq_desc_csum(int l3_offs, __be16 l3_proto,
int ip_hdr_len, int l4_proto)
{
u32 command;
@@ -2600,14 +2600,15 @@ static u32 mvpp2_skb_tx_csum(struct mvpp2_port *port, struct sk_buff *skb)
if (skb->ip_summed == CHECKSUM_PARTIAL) {
int ip_hdr_len = 0;
u8 l4_proto;
+ __be16 l3_proto = vlan_get_protocol(skb);

- if (skb->protocol == htons(ETH_P_IP)) {
+ if (l3_proto == htons(ETH_P_IP)) {
struct iphdr *ip4h = ip_hdr(skb);

/* Calculate IPv4 checksum and L4 checksum */
ip_hdr_len = ip4h->ihl;
l4_proto = ip4h->protocol;
- } else if (skb->protocol == htons(ETH_P_IPV6)) {
+ } else if (l3_proto == htons(ETH_P_IPV6)) {
struct ipv6hdr *ip6h = ipv6_hdr(skb);

/* Read l4_protocol from one of IPv6 extra headers */
@@ -2619,7 +2620,7 @@ static u32 mvpp2_skb_tx_csum(struct mvpp2_port *port, struct sk_buff *skb)
}

return mvpp2_txq_desc_csum(skb_network_offset(skb),
- skb->protocol, ip_hdr_len, l4_proto);
+ l3_proto, ip_hdr_len, l4_proto);
}

return MVPP2_TXD_L4_CSUM_NOT | MVPP2_TXD_IP_CSUM_DISABLE;
--
2.11.0

2018-10-05 21:53:39

by David Miller

Subject: Re: [PATCH net v2] net: mvpp2: Extract the correct ethtype from the skb for tx csum offload

From: Maxime Chevallier <[email protected]>
Date: Fri, 5 Oct 2018 09:04:40 +0200

> When offloading the L3 and L4 csum computation on TX, we need to extract
> the l3_proto from the ethtype, independently of the presence of a vlan
> tag.
>
> The actual driver uses skb->protocol as-is, resulting in packets with
> the wrong L4 checksum being sent when there's a vlan tag in the packet
> header and checksum offloading is enabled.
>
> This commit makes use of vlan_protocol_get() to get the correct ethtype
> regardless the presence of a vlan tag.
>
> Fixes: 3f518509dedc ("ethernet: Add new driver for Marvell Armada 375 network unit")
> Signed-off-by: Maxime Chevallier <[email protected]>
> ---
> V2: Use htons on values that can be swapped at compile-time, following
> Yan's comment. Fix the "Fixes" tag and a typo, following Sergei's comment.

Applied and queued up for -stable.