@@ -6,6 +6,8 @@
#ifndef __LINUX_NET_XDP_H__
#define __LINUX_NET_XDP_H__
+#include <linux/skbuff.h> /* skb_shared_info */
+
/**
* DOC: XDP RX-queue information
*
@@ -70,8 +72,19 @@ struct xdp_buff {
void *data_hard_start;
unsigned long handle;
struct xdp_rxq_info *rxq;
+ u32 frame_sz; /* frame size to deduce data_hard_end/reserved tailroom*/
};
+/* Reserve memory area at end-of data area.
+ *
+ * This macro reserves tailroom in the XDP buffer by limiting the
+ * XDP/BPF data access to data_hard_end. Notice same area (and size)
+ * is used for XDP_PASS, when constructing the SKB via build_skb().
+ */
+#define xdp_data_hard_end(xdp) \
+ ((xdp)->data_hard_start + (xdp)->frame_sz - \
+ SKB_DATA_ALIGN(sizeof(struct skb_shared_info)))
+
struct xdp_frame {
void *data;
u16 len;