rps: Add flag to skb to indicate rxhash is based on L4 tuple

The l4_rxhash flag was added to the skb structure to indicate
that the rxhash value was computed over the 4 tuple for the
packet which includes the port information in the encapsulated
transport packet.  This is used by the stack to preserve the
rxhash value in __skb_rx_tunnel.

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

2 files changed, 7 insertions, 4 deletions

diff --git a/net/core/dev.c b/net/core/dev.c
index 6578d9483043..e485cb37228f 100644
--- a/net/core/dev.c
+++ b/net/core/dev.c
@@ -2519,10 +2519,11 @@ static inline void ____napi_schedule(struct softnet_data *sd,
 
 /*
  * __skb_get_rxhash: calculate a flow hash based on src/dst addresses
- * and src/dst port numbers. Returns a non-zero hash number on success
- * and 0 on failure.
+ * and src/dst port numbers.  Sets rxhash in skb to non-zero hash value
+ * on success, zero indicates no valid hash.  Also, sets l4_rxhash in skb
+ * if hash is a canonical 4-tuple hash over transport ports.
  */
-__u32 __skb_get_rxhash(struct sk_buff *skb)
+void __skb_get_rxhash(struct sk_buff *skb)
 {
         int nhoff, hash = 0, poff;
         const struct ipv6hdr *ip6;
@@ -2574,6 +2575,7 @@ __u32 __skb_get_rxhash(struct sk_buff *skb)
                         ports.v32 = * (__force u32 *) (skb->data + nhoff);
                         if (ports.v16[1] < ports.v16[0])
                                 swap(ports.v16[0], ports.v16[1]);
+                        skb->l4_rxhash = 1;
                 }
         }
 
@@ -2586,7 +2588,7 @@ __u32 __skb_get_rxhash(struct sk_buff *skb)
                 hash = 1;
 
 done:
-        return hash;
+        skb->rxhash = hash;
 }
 EXPORT_SYMBOL(__skb_get_rxhash);
 
diff --git a/net/core/skbuff.c b/net/core/skbuff.c
index 27002dffe7ed..edb66f3e24f1 100644
--- a/net/core/skbuff.c
+++ b/net/core/skbuff.c
@@ -529,6 +529,7 @@ static void __copy_skb_header(struct sk_buff *new, const struct sk_buff *old)
         new->mac_header         = old->mac_header;
         skb_dst_copy(new, old);
         new->rxhash             = old->rxhash;
+        new->l4_rxhash          = old->l4_rxhash;
 #ifdef CONFIG_XFRM
         new->sp                 = secpath_get(old->sp);
 #endif