xdp: add MEM_TYPE_ZERO_COPY

Here, a new type of allocator support is added to the XDP return
API. A zero-copy allocated xdp_buff cannot be converted to an
xdp_frame. Instead is the buff has to be copied. This is not supported
at all in this commit.

Also, an opaque "handle" is added to xdp_buff. This can be used as a
context for the zero-copy allocator implementation.

Signed-off-by: Björn Töpel <bjorn.topel@intel.com>
Signed-off-by: Daniel Borkmann <daniel@iogearbox.net>

1 files changed, 10 insertions, 0 deletions

diff --git a/include/net/xdp.h b/include/net/xdp.h
index a3b71a4..2deea71 100644
--- a/include/net/xdp.h
+++ b/include/net/xdp.h
@@ -37,6 +37,7 @@ enum xdp_mem_type {
 	MEM_TYPE_PAGE_SHARED = 0, /* Split-page refcnt based model */
 	MEM_TYPE_PAGE_ORDER0,     /* Orig XDP full page model */
 	MEM_TYPE_PAGE_POOL,
+	MEM_TYPE_ZERO_COPY,
 	MEM_TYPE_MAX,
 };
 
@@ -51,6 +52,10 @@ struct xdp_mem_info {
 
 struct page_pool;
 
+struct zero_copy_allocator {
+	void (*free)(struct zero_copy_allocator *zca, unsigned long handle);
+};
+
 struct xdp_rxq_info {
 	struct net_device *dev;
 	u32 queue_index;
@@ -63,6 +68,7 @@ struct xdp_buff {
 	void *data_end;
 	void *data_meta;
 	void *data_hard_start;
+	unsigned long handle;
 	struct xdp_rxq_info *rxq;
 };
 
@@ -86,6 +92,10 @@ struct xdp_frame *convert_to_xdp_frame(struct xdp_buff *xdp)
 	int metasize;
 	int headroom;
 
+	/* TODO: implement clone, copy, use "native" MEM_TYPE */
+	if (xdp->rxq->mem.type == MEM_TYPE_ZERO_COPY)
+		return NULL;
+
 	/* Assure headroom is available for storing info */
 	headroom = xdp->data - xdp->data_hard_start;
 	metasize = xdp->data - xdp->data_meta;