5.4-stable review patch. If anyone has any objections, please let me know.
------------------
From: Xin Long <lucien.xin@xxxxxxxxx>
[ Upstream commit 62fafcd63139920eb25b3fbf154177ce3e6f3232 ]
NETIF_F_IP|IPV6_CSUM feature flag indicates UDP and TCP csum offload
while NETIF_F_HW_CSUM feature flag indicates ip generic csum offload
for HW, which includes not only for TCP/UDP csum, but also for other
protocols' csum like GRE's.
However, in skb_csum_hwoffload_help() it only checks features against
NETIF_F_CSUM_MASK(NETIF_F_HW|IP|IPV6_CSUM). So if it's a non TCP/UDP
packet and the features doesn't support NETIF_F_HW_CSUM, but supports
NETIF_F_IP|IPV6_CSUM only, it would still return 0 and leave the HW
to do csum.
This patch is to support ip generic csum processing by checking
NETIF_F_HW_CSUM for all protocols, and check (NETIF_F_IP_CSUM |
NETIF_F_IPV6_CSUM) only for TCP and UDP.
Note that we're using skb->csum_offset to check if it's a TCP/UDP
proctol, this might be fragile. However, as Alex said, for now we
only have a few L4 protocols that are requesting Tx csum offload,
we'd better fix this until a new protocol comes with a same csum
offset.
v1->v2:
- not extend skb->csum_not_inet, but use skb->csum_offset to tell
if it's an UDP/TCP csum packet.
v2->v3:
- add a note in the changelog, as Willem suggested.
Suggested-by: Alexander Duyck <alexander.duyck@xxxxxxxxx>
Signed-off-by: Xin Long <lucien.xin@xxxxxxxxx>
Signed-off-by: Jakub Kicinski <kuba@xxxxxxxxxx>
Stable-dep-of: 04c20a9356f2 ("net: skip offload for NETIF_F_IPV6_CSUM if ipv6 header contains extension")
Signed-off-by: Sasha Levin <sashal@xxxxxxxxxx>
---
net/core/dev.c | 13 ++++++++++++-
1 file changed, 12 insertions(+), 1 deletion(-)
diff --git a/net/core/dev.c b/net/core/dev.c
index 8f2f14df3610b..ff62b0027d600 100644
--- a/net/core/dev.c
+++ b/net/core/dev.c
@@ -3263,7 +3263,18 @@ int skb_csum_hwoffload_help(struct sk_buff *skb,
return !!(features & NETIF_F_SCTP_CRC) ? 0 :
skb_crc32c_csum_help(skb);
- return !!(features & NETIF_F_CSUM_MASK) ? 0 : skb_checksum_help(skb);
+ if (features & NETIF_F_HW_CSUM)
+ return 0;
+
+ if (features & (NETIF_F_IP_CSUM | NETIF_F_IPV6_CSUM)) {
+ switch (skb->csum_offset) {
+ case offsetof(struct tcphdr, check):
+ case offsetof(struct udphdr, check):
+ return 0;
+ }
+ }
+
+ return skb_checksum_help(skb);
}
EXPORT_SYMBOL(skb_csum_hwoffload_help);
--
2.43.0
