xsk: add Rx queue setup and mmap support

Another setsockopt (XDP_RX_QUEUE) is added to let the process allocate
a queue, where the kernel can pass completed Rx frames from the kernel
to user process.

The mmapping of the queue is done using the XDP_PGOFF_RX_QUEUE offset.

Signed-off-by: Björn Töpel <bjorn.topel@intel.com>
Signed-off-by: Alexei Starovoitov <ast@kernel.org>

1 files changed, 16 insertions, 0 deletions

diff --git a/include/uapi/linux/if_xdp.h b/include/uapi/linux/if_xdp.h
index 975661e1baca..65324558829d 100644
--- a/include/uapi/linux/if_xdp.h
+++ b/include/uapi/linux/if_xdp.h
@@ -22,6 +22,7 @@
 #include <linux/types.h>
 
 /* XDP socket options */
+#define XDP_RX_RING			1
 #define XDP_UMEM_REG			3
 #define XDP_UMEM_FILL_RING		4
 
@@ -33,13 +34,28 @@ struct xdp_umem_reg {
 };
 
 /* Pgoff for mmaping the rings */
+#define XDP_PGOFF_RX_RING			  0
 #define XDP_UMEM_PGOFF_FILL_RING	0x100000000
 
+struct xdp_desc {
+	__u32 idx;
+	__u32 len;
+	__u16 offset;
+	__u8 flags;
+	__u8 padding[5];
+};
+
 struct xdp_ring {
 	__u32 producer __attribute__((aligned(64)));
 	__u32 consumer __attribute__((aligned(64)));
 };
 
+/* Used for the RX and TX queues for packets */
+struct xdp_rxtx_ring {
+	struct xdp_ring ptrs;
+	struct xdp_desc desc[0] __attribute__((aligned(64)));
+};
+
 /* Used for the fill and completion queues for buffers */
 struct xdp_umem_ring {
 	struct xdp_ring ptrs;