From 62fafcd63139920eb25b3fbf154177ce3e6f3232 Mon Sep 17 00:00:00 2001 From: Xin Long Date: Thu, 28 Jan 2021 17:18:31 +0800 Subject: [PATCH] net: support ip generic csum processing in skb_csum_hwoffload_help 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 Signed-off-by: Xin Long Signed-off-by: Jakub Kicinski --- 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 6df3f1bcdc68..aae116d059da 100644 --- a/net/core/dev.c +++ b/net/core/dev.c @@ -3621,7 +3621,18 @@ 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); -- 2.11.0