net: Infrastructure for checksum unnecessary conversions

For normal path, added skb_checksum_try_convert which is called
to attempt to convert CHECKSUM_UNNECESSARY to CHECKSUM_COMPLETE. The
primary condition to allow this is that ip_summed is CHECKSUM_NONE
and csum_valid is true, which will be the state after consuming
a CHECKSUM_UNNECESSARY.

For GRO path, added skb_gro_checksum_try_convert which is the GRO
analogue of skb_checksum_try_convert. The primary condition to allow
this is that NAPI_GRO_CB(skb)->csum_cnt == 0 and
NAPI_GRO_CB(skb)->csum_valid is set. This implies that we have consumed
all available CHECKSUM_UNNECESSARY checksums in the GRO path.

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

diff --git a/include/linux/netdevice.h b/include/linux/netdevice.h
index a0ab6d9d400aabb86e65501ae984174b4db89859..5be20a7bbb0da01b779c4faa9904691df6734f1f 100644 (file)
--- a/include/linux/netdevice.h
+++ b/include/linux/netdevice.h
@@ -2233,6 +2233,26 @@ static inline void skb_gro_incr_csum_unnecessary(struct sk_buff *skb)
 #define skb_gro_checksum_simple_validate(skb)                          \
        __skb_gro_checksum_validate(skb, 0, false, 0, null_compute_pseudo)
 
+static inline bool __skb_gro_checksum_convert_check(struct sk_buff *skb)
+{
+       return (NAPI_GRO_CB(skb)->csum_cnt == 0 &&
+               !NAPI_GRO_CB(skb)->csum_valid);
+}
+
+static inline void __skb_gro_checksum_convert(struct sk_buff *skb,
+                                             __sum16 check, __wsum pseudo)
+{
+       NAPI_GRO_CB(skb)->csum = ~pseudo;
+       NAPI_GRO_CB(skb)->csum_valid = 1;
+}
+
+#define skb_gro_checksum_try_convert(skb, proto, check, compute_pseudo)        \
+do {                                                                   \
+       if (__skb_gro_checksum_convert_check(skb))                      \
+               __skb_gro_checksum_convert(skb, check,                  \
+                                          compute_pseudo(skb, proto)); \
+} while (0)
+
 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 23710a243439b19e1c21fec09ba5ed55522198cf..02529fcad1ac2bee14680c17e539e10abe472d2c 100644 (file)
--- a/include/linux/skbuff.h
+++ b/include/linux/skbuff.h
@@ -2942,6 +2942,26 @@ static inline __wsum null_compute_pseudo(struct sk_buff *skb, int proto)
 #define skb_checksum_simple_validate(skb)                              \
        __skb_checksum_validate(skb, 0, true, false, 0, null_compute_pseudo)
 
+static inline bool __skb_checksum_convert_check(struct sk_buff *skb)
+{
+       return (skb->ip_summed == CHECKSUM_NONE &&
+               skb->csum_valid && !skb->csum_bad);
+}
+
+static inline void __skb_checksum_convert(struct sk_buff *skb,
+                                         __sum16 check, __wsum pseudo)
+{
+       skb->csum = ~pseudo;
+       skb->ip_summed = CHECKSUM_COMPLETE;
+}
+
+#define skb_checksum_try_convert(skb, proto, check, compute_pseudo)    \
+do {                                                                   \
+       if (__skb_checksum_convert_check(skb))                          \
+               __skb_checksum_convert(skb, check,                      \
+                                      compute_pseudo(skb, proto));     \
+} while (0)
+
 #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)