xdp: introduce a new xdp_frame type

This is needed to convert drivers tuntap and virtio_net.

This is a generalization of what is done inside cpumap, which will be
converted later.

Signed-off-by: Jesper Dangaard Brouer <brouer@redhat.com>
Signed-off-by: David S. Miller <davem@davemloft.net>

diff --git a/include/net/xdp.h b/include/net/xdp.h
index 15f8ade008b5f58e9d84601120a8de319099bf1d..756c42811e7809d238505a37313ed72d230603dc 100644 (file)
--- a/include/net/xdp.h
+++ b/include/net/xdp.h
@@ -58,6 +58,46 @@ struct xdp_buff {
        struct xdp_rxq_info *rxq;
 };
 
+struct xdp_frame {
+       void *data;
+       u16 len;
+       u16 headroom;
+       u16 metasize;
+       /* Lifetime of xdp_rxq_info is limited to NAPI/enqueue time,
+        * while mem info is valid on remote CPU.
+        */
+       struct xdp_mem_info mem;
+};
+
+/* Convert xdp_buff to xdp_frame */
+static inline
+struct xdp_frame *convert_to_xdp_frame(struct xdp_buff *xdp)
+{
+       struct xdp_frame *xdp_frame;
+       int metasize;
+       int headroom;
+
+       /* Assure headroom is available for storing info */
+       headroom = xdp->data - xdp->data_hard_start;
+       metasize = xdp->data - xdp->data_meta;
+       metasize = metasize > 0 ? metasize : 0;
+       if (unlikely((headroom - metasize) < sizeof(*xdp_frame)))
+               return NULL;
+
+       /* Store info in top of packet */
+       xdp_frame = xdp->data_hard_start;
+
+       xdp_frame->data = xdp->data;
+       xdp_frame->len  = xdp->data_end - xdp->data;
+       xdp_frame->headroom = headroom - sizeof(*xdp_frame);
+       xdp_frame->metasize = metasize;
+
+       /* rxq only valid until napi_schedule ends, convert to xdp_mem_info */
+       xdp_frame->mem = xdp->rxq->mem;
+
+       return xdp_frame;
+}
+
 static inline
 void xdp_return_frame(void *data, struct xdp_mem_info *mem)
 {