xdp: introduce xdp_get_shared_info_from_{buff, frame} utility routines

Introduce xdp_get_shared_info_from_{buff,frame} utility routines to get
skb_shared_info from xdp buffer/frame pointer.
xdp_get_shared_info_from_{buff,frame} will be used to implement xdp
multi-buffer support

Signed-off-by: Lorenzo Bianconi <lorenzo@kernel.org>
Signed-off-by: David S. Miller <davem@davemloft.net>

diff --git a/include/net/xdp.h b/include/net/xdp.h
index 609f819..d3005be 100644 (file)
--- a/include/net/xdp.h
+++ b/include/net/xdp.h
@@ -85,6 +85,12 @@ struct xdp_buff {
        ((xdp)->data_hard_start + (xdp)->frame_sz -     \
         SKB_DATA_ALIGN(sizeof(struct skb_shared_info)))
 
+static inline struct skb_shared_info *
+xdp_get_shared_info_from_buff(struct xdp_buff *xdp)
+{
+       return (struct skb_shared_info *)xdp_data_hard_end(xdp);
+}
+
 struct xdp_frame {
        void *data;
        u16 len;
@@ -98,6 +104,15 @@ struct xdp_frame {
        struct net_device *dev_rx; /* used by cpumap */
 };
 
+static inline struct skb_shared_info *
+xdp_get_shared_info_from_frame(struct xdp_frame *frame)
+{
+       void *data_hard_start = frame->data - frame->headroom - sizeof(*frame);
+
+       return (struct skb_shared_info *)(data_hard_start + frame->frame_sz -
+                               SKB_DATA_ALIGN(sizeof(struct skb_shared_info)));
+}
+
 /* Clear kernel pointers in xdp_frame */
 static inline void xdp_scrub_frame(struct xdp_frame *frame)
 {