net: Infrastructure for CHECKSUM_PARTIAL with remote checsum offload

This patch adds infrastructure so that remote checksum offload can
set CHECKSUM_PARTIAL instead of calling csum_partial and writing
the modfied checksum field.

Add skb_remcsum_adjust_partial function to set an skb for using
CHECKSUM_PARTIAL with remote checksum offload.  Changed
skb_remcsum_process and skb_gro_remcsum_process to take a boolean
argument to indicate if checksum partial can be set or the
checksum needs to be modified using the normal algorithm.

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 30310a6..4f04443 100644 (file)
--- a/drivers/net/vxlan.c
+++ b/drivers/net/vxlan.c
@@ -580,7 +580,7 @@ static struct vxlanhdr *vxlan_gro_remcsum(struct sk_buff *skb,
        }
 
        skb_gro_remcsum_process(skb, (void *)vh + hdrlen,
-                               start, offset, grc);
+                               start, offset, grc, true);
 
        skb->remcsum_offload = 1;
 
@@ -1171,7 +1171,7 @@ static struct vxlanhdr *vxlan_remcsum(struct sk_buff *skb, struct vxlanhdr *vh,
 
        vh = (struct vxlanhdr *)(udp_hdr(skb) + 1);
 
-       skb_remcsum_process(skb, (void *)vh + hdrlen, start, offset);
+       skb_remcsum_process(skb, (void *)vh + hdrlen, start, offset, true);
 
        return vh;
 }

diff --git a/include/linux/netdevice.h b/include/linux/netdevice.h
index 43fd0a4..5897b4e 100644 (file)
--- a/include/linux/netdevice.h
+++ b/include/linux/netdevice.h
@@ -1923,6 +1923,9 @@ struct napi_gro_cb {
        /* Number of segments aggregated. */
        u16     count;
 
+       /* Start offset for remote checksum offload */
+       u16     gro_remcsum_start;
+
        /* jiffies when first packet was created/queued */
        unsigned long age;
 
@@ -2244,6 +2247,12 @@ static inline void skb_gro_postpull_rcsum(struct sk_buff *skb,
 
 __sum16 __skb_gro_checksum_complete(struct sk_buff *skb);
 
+static inline bool skb_at_gro_remcsum_start(struct sk_buff *skb)
+{
+       return (NAPI_GRO_CB(skb)->gro_remcsum_start - skb_headroom(skb) ==
+               skb_gro_offset(skb));
+}
+
 static inline bool __skb_gro_checksum_validate_needed(struct sk_buff *skb,
                                                      bool zero_okay,
                                                      __sum16 check)
@@ -2251,6 +2260,7 @@ static inline bool __skb_gro_checksum_validate_needed(struct sk_buff *skb,
        return ((skb->ip_summed != CHECKSUM_PARTIAL ||
                skb_checksum_start_offset(skb) <
                 skb_gro_offset(skb)) &&
+               !skb_at_gro_remcsum_start(skb) &&
                NAPI_GRO_CB(skb)->csum_cnt == 0 &&
                (!zero_okay || check));
 }
@@ -2337,12 +2347,19 @@ static inline void skb_gro_remcsum_init(struct gro_remcsum *grc)
 
 static inline void skb_gro_remcsum_process(struct sk_buff *skb, void *ptr,
                                           int start, int offset,
-                                          struct gro_remcsum *grc)
+                                          struct gro_remcsum *grc,
+                                          bool nopartial)
 {
        __wsum delta;
 
        BUG_ON(!NAPI_GRO_CB(skb)->csum_valid);
 
+       if (!nopartial) {
+               NAPI_GRO_CB(skb)->gro_remcsum_start =
+                   ((unsigned char *)ptr + start) - skb->head;
+               return;
+       }
+
        delta = remcsum_adjust(ptr, NAPI_GRO_CB(skb)->csum, start, offset);
 
        /* Adjust skb->csum since we changed the packet */

diff --git a/include/linux/skbuff.h b/include/linux/skbuff.h
index da6028a..30007af 100644 (file)
--- a/include/linux/skbuff.h
+++ b/include/linux/skbuff.h
@@ -3104,16 +3104,29 @@ do {                                                                    \
                                       compute_pseudo(skb, proto));     \
 } while (0)
 
+static inline void skb_remcsum_adjust_partial(struct sk_buff *skb, void *ptr,
+                                             u16 start, u16 offset)
+{
+       skb->ip_summed = CHECKSUM_PARTIAL;
+       skb->csum_start = ((unsigned char *)ptr + start) - skb->head;
+       skb->csum_offset = offset - start;
+}
+
 /* 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)
+                                      int start, int offset, bool nopartial)
 {
        __wsum delta;
 
+       if (!nopartial) {
+               skb_remcsum_adjust_partial(skb, ptr, start, offset);
+               return;
+       }
+
         if (unlikely(skb->ip_summed != CHECKSUM_COMPLETE)) {
                __skb_checksum_complete(skb);
                skb_postpull_rcsum(skb, skb->data, ptr - (void *)skb->data);

diff --git a/net/core/dev.c b/net/core/dev.c
index d030575..48c6ecb 100644 (file)
--- a/net/core/dev.c
+++ b/net/core/dev.c
@@ -4024,6 +4024,7 @@ static enum gro_result dev_gro_receive(struct napi_struct *napi, struct sk_buff
                NAPI_GRO_CB(skb)->flush = 0;
                NAPI_GRO_CB(skb)->free = 0;
                NAPI_GRO_CB(skb)->udp_mark = 0;
+               NAPI_GRO_CB(skb)->gro_remcsum_start = 0;
 
                /* Setup for GRO checksum validation */
                switch (skb->ip_summed) {

diff --git a/net/ipv4/fou.c b/net/ipv4/fou.c
index 7fa8d36..d320f57 100644 (file)
--- a/net/ipv4/fou.c
+++ b/net/ipv4/fou.c
@@ -75,7 +75,7 @@ static struct guehdr *gue_remcsum(struct sk_buff *skb, struct guehdr *guehdr,
                return NULL;
        guehdr = (struct guehdr *)&udp_hdr(skb)[1];
 
-       skb_remcsum_process(skb, (void *)guehdr + hdrlen, start, offset);
+       skb_remcsum_process(skb, (void *)guehdr + hdrlen, start, offset, true);
 
        return guehdr;
 }
@@ -230,7 +230,7 @@ static struct guehdr *gue_gro_remcsum(struct sk_buff *skb, unsigned int off,
        }
 
        skb_gro_remcsum_process(skb, (void *)guehdr + hdrlen,
-                               start, offset, grc);
+                               start, offset, grc, true);
 
        skb->remcsum_offload = 1;