From 62fafcd63139920eb25b3fbf154177ce3e6f3232 Mon Sep 17 00:00:00 2001 From: Xin Long Date: Thu, 28 Jan 2021 17:18:31 +0800 Subject: 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); -- cgit v1.2.3 From efa1a65c7e1946ff174c56d36bf015ff9e11c4a1 Mon Sep 17 00:00:00 2001 From: Xin Long Date: Thu, 28 Jan 2021 17:18:32 +0800 Subject: ip_gre: add csum offload support for gre header This patch is to add csum offload support for gre header: On the TX path in gre_build_header(), when CHECKSUM_PARTIAL's set for inner proto, it will calculate the csum for outer proto, and inner csum will be offloaded later. Otherwise, CHECKSUM_PARTIAL and csum_start/offset will be set for outer proto, and the outer csum will be offloaded later. On the GSO path in gre_gso_segment(), when CHECKSUM_PARTIAL is not set for inner proto and the hardware supports csum offload, CHECKSUM_PARTIAL and csum_start/offset will be set for outer proto, and outer csum will be offloaded later. Otherwise, it will do csum for outer proto by calling gso_make_checksum(). Note that SCTP has to do the csum by itself for non GSO path in sctp_packet_pack(), as gre_build_header() can't handle the csum with CHECKSUM_PARTIAL set for SCTP CRC csum offload. v1->v2: - remove the SCTP part, as GRE dev doesn't support SCTP CRC CSUM and it will always do checksum for SCTP in sctp_packet_pack() when it's not a GSO packet. Signed-off-by: Xin Long Signed-off-by: Jakub Kicinski --- include/net/gre.h | 19 +++++++------------ net/ipv4/gre_offload.c | 15 +++++++++++++-- 2 files changed, 20 insertions(+), 14 deletions(-) diff --git a/include/net/gre.h b/include/net/gre.h index b60f212c16c6..4e209708b754 100644 --- a/include/net/gre.h +++ b/include/net/gre.h @@ -106,17 +106,6 @@ static inline __be16 gre_tnl_flags_to_gre_flags(__be16 tflags) return flags; } -static inline __sum16 gre_checksum(struct sk_buff *skb) -{ - __wsum csum; - - if (skb->ip_summed == CHECKSUM_PARTIAL) - csum = lco_csum(skb); - else - csum = skb_checksum(skb, 0, skb->len, 0); - return csum_fold(csum); -} - static inline void gre_build_header(struct sk_buff *skb, int hdr_len, __be16 flags, __be16 proto, __be32 key, __be32 seq) @@ -146,7 +135,13 @@ static inline void gre_build_header(struct sk_buff *skb, int hdr_len, !(skb_shinfo(skb)->gso_type & (SKB_GSO_GRE | SKB_GSO_GRE_CSUM))) { *ptr = 0; - *(__sum16 *)ptr = gre_checksum(skb); + if (skb->ip_summed == CHECKSUM_PARTIAL) { + *(__sum16 *)ptr = csum_fold(lco_csum(skb)); + } else { + skb->ip_summed = CHECKSUM_PARTIAL; + skb->csum_start = skb_transport_header(skb) - skb->head; + skb->csum_offset = sizeof(*greh); + } } } } diff --git a/net/ipv4/gre_offload.c b/net/ipv4/gre_offload.c index 10bc49bde9a1..1121a9d5fed9 100644 --- a/net/ipv4/gre_offload.c +++ b/net/ipv4/gre_offload.c @@ -15,10 +15,10 @@ static struct sk_buff *gre_gso_segment(struct sk_buff *skb, netdev_features_t features) { int tnl_hlen = skb_inner_mac_header(skb) - skb_transport_header(skb); + bool need_csum, offload_csum, gso_partial, need_ipsec; struct sk_buff *segs = ERR_PTR(-EINVAL); u16 mac_offset = skb->mac_header; __be16 protocol = skb->protocol; - bool need_csum, gso_partial; u16 mac_len = skb->mac_len; int gre_offset, outer_hlen; @@ -47,6 +47,11 @@ static struct sk_buff *gre_gso_segment(struct sk_buff *skb, if (need_csum) features &= ~NETIF_F_SCTP_CRC; + need_ipsec = skb_dst(skb) && dst_xfrm(skb_dst(skb)); + /* Try to offload checksum if possible */ + offload_csum = !!(need_csum && !need_ipsec && + (skb->dev->features & NETIF_F_HW_CSUM)); + /* segment inner packet. */ segs = skb_mac_gso_segment(skb, features); if (IS_ERR_OR_NULL(segs)) { @@ -100,7 +105,13 @@ static struct sk_buff *gre_gso_segment(struct sk_buff *skb, } *(pcsum + 1) = 0; - *pcsum = gso_make_checksum(skb, 0); + if (skb->encapsulation || !offload_csum) { + *pcsum = gso_make_checksum(skb, 0); + } else { + skb->ip_summed = CHECKSUM_PARTIAL; + skb->csum_start = skb_transport_header(skb) - skb->head; + skb->csum_offset = sizeof(*greh); + } } while ((skb = skb->next)); out: return segs; -- cgit v1.2.3