net: add skb functions to process remote checksum offload

This patch adds skb_remcsum_process and skb_gro_remcsum_process to
perform the appropriate adjustments to the skb when receiving
remote checksum offload.

Updated vxlan and gue to use these functions.

Tested: Ran TCP_RR and TCP_STREAM netperf for VXLAN and GUE, did
not see any change in performance.

Signed-off-by: Tom Herbert <therbert@google.com>
Signed-off-by: David S. Miller <davem@davemloft.net>

diff --git a/drivers/net/vxlan.c b/drivers/net/vxlan.c
index 31bac2a..c184717 100644 (file)
--- a/drivers/net/vxlan.c
+++ b/drivers/net/vxlan.c
@@ -558,7 +558,6 @@ static struct vxlanhdr *vxlan_gro_remcsum(struct sk_buff *skb,
                                          u32 data)
 {
        size_t start, offset, plen;
-       __wsum delta;
 
        if (skb->remcsum_offload)
                return vh;
@@ -580,12 +579,7 @@ static struct vxlanhdr *vxlan_gro_remcsum(struct sk_buff *skb,
                        return NULL;
        }
 
-       delta = remcsum_adjust((void *)vh + hdrlen,
-                              NAPI_GRO_CB(skb)->csum, start, offset);
-
-       /* Adjust skb->csum since we changed the packet */
-       skb->csum = csum_add(skb->csum, delta);
-       NAPI_GRO_CB(skb)->csum = csum_add(NAPI_GRO_CB(skb)->csum, delta);
+       skb_gro_remcsum_process(skb, (void *)vh + hdrlen, start, offset);
 
        skb->remcsum_offload = 1;
 
@@ -1159,7 +1153,6 @@ static struct vxlanhdr *vxlan_remcsum(struct sk_buff *skb, struct vxlanhdr *vh,
                                      size_t hdrlen, u32 data)
 {
        size_t start, offset, plen;
-       __wsum delta;
 
        if (skb->remcsum_offload) {
                /* Already processed in GRO path */
@@ -1179,14 +1172,7 @@ static struct vxlanhdr *vxlan_remcsum(struct sk_buff *skb, struct vxlanhdr *vh,
 
        vh = (struct vxlanhdr *)(udp_hdr(skb) + 1);
 
-       if (unlikely(skb->ip_summed != CHECKSUM_COMPLETE))
-               __skb_checksum_complete(skb);
-
-       delta = remcsum_adjust((void *)vh + hdrlen,
-                              skb->csum, start, offset);
-
-       /* Adjust skb->csum since we changed the packet */
-       skb->csum = csum_add(skb->csum, delta);
+       skb_remcsum_process(skb, (void *)vh + hdrlen, start, offset);
 
        return vh;
 }

diff --git a/include/linux/netdevice.h b/include/linux/netdevice.h
index 16251e9..1347ac5 100644 (file)
--- a/include/linux/netdevice.h
+++ b/include/linux/netdevice.h
@@ -2318,6 +2318,21 @@ do {                                                                     \
                                           compute_pseudo(skb, proto)); \
 } while (0)
 
+static inline void skb_gro_remcsum_process(struct sk_buff *skb, void *ptr,
+                                          int start, int offset)
+{
+       __wsum delta;
+
+       BUG_ON(!NAPI_GRO_CB(skb)->csum_valid);
+
+       delta = remcsum_adjust(ptr, NAPI_GRO_CB(skb)->csum, start, offset);
+
+       /* Adjust skb->csum since we changed the packet */
+       skb->csum = csum_add(skb->csum, delta);
+       NAPI_GRO_CB(skb)->csum = csum_add(NAPI_GRO_CB(skb)->csum, delta);
+}
+
+
 static inline int dev_hard_header(struct sk_buff *skb, struct net_device *dev,
                                  unsigned short type,
                                  const void *daddr, const void *saddr,

diff --git a/include/linux/skbuff.h b/include/linux/skbuff.h
index 2748ff6..5405dfe 100644 (file)
--- a/include/linux/skbuff.h
+++ b/include/linux/skbuff.h
@@ -3099,6 +3099,27 @@ do {                                                                     \
                                       compute_pseudo(skb, proto));     \
 } while (0)
 
+/* Update skbuf and packet to reflect the remote checksum offload operation.
+ * When called, ptr indicates the starting point for skb->csum when
+ * ip_summed is CHECKSUM_COMPLETE. If we need create checksum complete
+ * here, skb_postpull_rcsum is done so skb->csum start is ptr.
+ */
+static inline void skb_remcsum_process(struct sk_buff *skb, void *ptr,
+                                      int start, int offset)
+{
+       __wsum delta;
+
+        if (unlikely(skb->ip_summed != CHECKSUM_COMPLETE)) {
+               __skb_checksum_complete(skb);
+               skb_postpull_rcsum(skb, skb->data, ptr - (void *)skb->data);
+       }
+
+       delta = remcsum_adjust(ptr, skb->csum, start, offset);
+
+       /* Adjust skb->csum since we changed the packet */
+       skb->csum = csum_add(skb->csum, delta);
+}
+
 #if defined(CONFIG_NF_CONNTRACK) || defined(CONFIG_NF_CONNTRACK_MODULE)
 void nf_conntrack_destroy(struct nf_conntrack *nfct);
 static inline void nf_conntrack_put(struct nf_conntrack *nfct)

diff --git a/net/ipv4/fou.c b/net/ipv4/fou.c
index 3bc0cf0..92ddea1 100644 (file)
--- a/net/ipv4/fou.c
+++ b/net/ipv4/fou.c
@@ -70,7 +70,6 @@ static struct guehdr *gue_remcsum(struct sk_buff *skb, struct guehdr *guehdr,
        size_t start = ntohs(pd[0]);
        size_t offset = ntohs(pd[1]);
        size_t plen = hdrlen + max_t(size_t, offset + sizeof(u16), start);
-       __wsum delta;
 
        if (skb->remcsum_offload) {
                /* Already processed in GRO path */
@@ -82,14 +81,7 @@ static struct guehdr *gue_remcsum(struct sk_buff *skb, struct guehdr *guehdr,
                return NULL;
        guehdr = (struct guehdr *)&udp_hdr(skb)[1];
 
-       if (unlikely(skb->ip_summed != CHECKSUM_COMPLETE))
-               __skb_checksum_complete(skb);
-
-       delta = remcsum_adjust((void *)guehdr + hdrlen,
-                              skb->csum, start, offset);
-
-       /* Adjust skb->csum since we changed the packet */
-       skb->csum = csum_add(skb->csum, delta);
+       skb_remcsum_process(skb, (void *)guehdr + hdrlen, start, offset);
 
        return guehdr;
 }
@@ -228,7 +220,6 @@ static struct guehdr *gue_gro_remcsum(struct sk_buff *skb, unsigned int off,
        size_t start = ntohs(pd[0]);
        size_t offset = ntohs(pd[1]);
        size_t plen = hdrlen + max_t(size_t, offset + sizeof(u16), start);
-       __wsum delta;
 
        if (skb->remcsum_offload)
                return guehdr;
@@ -243,12 +234,7 @@ static struct guehdr *gue_gro_remcsum(struct sk_buff *skb, unsigned int off,
                        return NULL;
        }
 
-       delta = remcsum_adjust((void *)guehdr + hdrlen,
-                              NAPI_GRO_CB(skb)->csum, start, offset);
-
-       /* Adjust skb->csum since we changed the packet */
-       skb->csum = csum_add(skb->csum, delta);
-       NAPI_GRO_CB(skb)->csum = csum_add(NAPI_GRO_CB(skb)->csum, delta);
+       skb_gro_remcsum_process(skb, (void *)guehdr + hdrlen, start, offset);
 
        skb->remcsum_offload = 1;