5.4-stable review patch. If anyone has any objections, please let me know.
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From: Xin Long lucien.xin@gmail.com
[ 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@gmail.com Signed-off-by: Xin Long lucien.xin@gmail.com Signed-off-by: Jakub Kicinski kuba@kernel.org Stable-dep-of: 04c20a9356f2 ("net: skip offload for NETIF_F_IPV6_CSUM if ipv6 header contains extension") Signed-off-by: Sasha Levin sashal@kernel.org --- 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);