[PATCH v9 bpf-next 07/14] net: xdp: add multi-buff support to xdp_build_skb_from_frame

[Lorenzo Bianconi <lorenzo@xxxxxxxxxx>]

Introduce xdp multi-buff support to
__xdp_build_skb_from_frame/xdp_build_skb_from_frame
utility routines.

Signed-off-by: Lorenzo Bianconi <lorenzo@xxxxxxxxxx>
---
 net/core/xdp.c | 13 +++++++++++++
 1 file changed, 13 insertions(+)

diff --git a/net/core/xdp.c b/net/core/xdp.c
index f61c63115c95..71bedf6049a1 100644
--- a/net/core/xdp.c
+++ b/net/core/xdp.c
@@ -582,9 +582,15 @@ struct sk_buff *__xdp_build_skb_from_frame(struct xdp_frame *xdpf,
 					   struct sk_buff *skb,
 					   struct net_device *dev)
 {
+	struct skb_shared_info *sinfo = xdp_get_shared_info_from_frame(xdpf);
 	unsigned int headroom, frame_size;
+	int i, num_frags = 0;
 	void *hard_start;
 
+	/* xdp multi-buff frame */
+	if (unlikely(xdp_frame_is_mb(xdpf)))
+		num_frags = sinfo->nr_frags;
+
 	/* Part of headroom was reserved to xdpf */
 	headroom = sizeof(*xdpf) + xdpf->headroom;
 
@@ -603,6 +609,13 @@ struct sk_buff *__xdp_build_skb_from_frame(struct xdp_frame *xdpf,
 	if (xdpf->metasize)
 		skb_metadata_set(skb, xdpf->metasize);
 
+	for (i = 0; i < num_frags; i++)
+		skb_add_rx_frag(skb, skb_shinfo(skb)->nr_frags,
+				skb_frag_page(&sinfo->frags[i]),
+				skb_frag_off(&sinfo->frags[i]),
+				skb_frag_size(&sinfo->frags[i]),
+				xdpf->frame_sz);
+
 	/* Essential SKB info: protocol and skb->dev */
 	skb->protocol = eth_type_trans(skb, dev);
 
-- 
2.31.1