[bpf-next V3 PATCH 05/15] xdp: introduce a new xdp_frame type

Jesper Dangaard Brouer
2018-03-09T20:55:31Z

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>
---
include/net/xdp.h | 40 ++++++++++++++++++++++++++++++++++++++++
1 file changed, 40 insertions(+)

diff --git a/include/net/xdp.h b/include/net/xdp.h
index 1ee154fe0be6..13f71a15c79f 100644
--- a/include/net/xdp.h
+++ b/include/net/xdp.h
@@ -59,6 +59,46 @@ 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)
{