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.
Signed-off-by: Xin Long <lucien....@gmail.com>
---
include/net/gre.h | 20 ++++++++------------
net/ipv4/gre_offload.c | 16 ++++++++++++++--
net/sctp/output.c | 1 +
3 files changed, 23 insertions(+), 14 deletions(-)
diff --git a/include/net/gre.h b/include/net/gre.h
index b60f212..250b2fb 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 +135,14 @@ 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->csum_type = CSUM_T_IP_GENERIC;
+ 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 10bc49b..12d6996 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 +105,14 @@ 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->csum_type = CSUM_T_IP_GENERIC;
+ 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;
diff --git a/net/sctp/output.c b/net/sctp/output.c
index a8cf0191..52e12df 100644
--- a/net/sctp/output.c
+++ b/net/sctp/output.c
@@ -515,6 +515,7 @@ static int sctp_packet_pack(struct sctp_packet *packet,
return 1;
if (!(tp->dst->dev->features & NETIF_F_SCTP_CRC) ||
+ tp->dst->dev->type == ARPHRD_IPGRE ||
dst_xfrm(tp->dst) || packet->ipfragok || tp->encap_port) {
struct sctphdr *sh =
(struct sctphdr *)skb_transport_header(head);
--
2.1.0
