Commit 503d539a authored by Yuya Kusakabe's avatar Yuya Kusakabe Committed by Daniel Borkmann
Browse files

virtio_net: Add XDP meta data support 

Implement support for transferring XDP meta data into skb for
virtio_net driver; before calling into the program, xdp.data_meta points
to xdp.data, where on program return with pass verdict, we call
into skb_metadata_set().

Tested with the script at
https://github.com/higebu/virtio_net-xdp-metadata-test

.

Signed-off-by: default avatarYuya Kusakabe <yuya.kusakabe@gmail.com>
Signed-off-by: default avatarDaniel Borkmann <daniel@iogearbox.net>
Acked-by: default avatarJason Wang <jasowang@redhat.com>
Acked-by: default avatarMichael S. Tsirkin <mst@redhat.com>
Link: https://lore.kernel.org/bpf/20200225033212.437563-2-yuya.kusakabe@gmail.com
parent f1d4884d

drivers/net/virtio_net.c

+32 −20
Original line number Diff line number Diff line
@@ -371,7 +371,7 @@ static struct sk_buff *page_to_skb(struct virtnet_info *vi, 
				   struct receive_queue *rq,

				   struct page *page, unsigned int offset,

				   unsigned int len, unsigned int truesize,

				   bool hdr_valid)

				   bool hdr_valid, unsigned int metasize)

{

	struct sk_buff *skb;

	struct virtio_net_hdr_mrg_rxbuf *hdr;
@@ -393,6 +393,7 @@ static struct sk_buff *page_to_skb(struct virtnet_info *vi, 
	else

		hdr_padded_len = sizeof(struct padded_vnet_hdr);



	/* hdr_valid means no XDP, so we can copy the vnet header */

	if (hdr_valid)

		memcpy(hdr, p, hdr_len);
@@ -405,6 +406,11 @@ static struct sk_buff *page_to_skb(struct virtnet_info *vi, 
		copy = skb_tailroom(skb);

	skb_put_data(skb, p, copy);



	if (metasize) {

		__skb_pull(skb, metasize);

		skb_metadata_set(skb, metasize);

	}



	len -= copy;

	offset += copy;
@@ -450,10 +456,6 @@ static int __virtnet_xdp_xmit_one(struct virtnet_info *vi, 
	struct virtio_net_hdr_mrg_rxbuf *hdr;

	int err;



	/* virtqueue want to use data area in-front of packet */

	if (unlikely(xdpf->metasize > 0))

		return -EOPNOTSUPP;



	if (unlikely(xdpf->headroom < vi->hdr_len))

		return -EOVERFLOW;
@@ -644,6 +646,7 @@ static struct sk_buff *receive_small(struct net_device *dev, 
	unsigned int delta = 0;

	struct page *xdp_page;

	int err;

	unsigned int metasize = 0;



	len -= vi->hdr_len;

	stats->bytes += len;
@@ -683,8 +686,8 @@ static struct sk_buff *receive_small(struct net_device *dev, 


		xdp.data_hard_start = buf + VIRTNET_RX_PAD + vi->hdr_len;

		xdp.data = xdp.data_hard_start + xdp_headroom;

		xdp_set_data_meta_invalid(&xdp);

		xdp.data_end = xdp.data + len;

		xdp.data_meta = xdp.data;

		xdp.rxq = &rq->xdp_rxq;

		orig_data = xdp.data;

		act = bpf_prog_run_xdp(xdp_prog, &xdp);
@@ -695,6 +698,7 @@ static struct sk_buff *receive_small(struct net_device *dev, 
			/* Recalculate length in case bpf program changed it */

			delta = orig_data - xdp.data;

			len = xdp.data_end - xdp.data;

			metasize = xdp.data - xdp.data_meta;

			break;

		case XDP_TX:

			stats->xdp_tx++;
@@ -740,6 +744,9 @@ static struct sk_buff *receive_small(struct net_device *dev, 
		memcpy(skb_vnet_hdr(skb), buf, vi->hdr_len);

	} /* keep zeroed vnet hdr since XDP is loaded */



	if (metasize)

		skb_metadata_set(skb, metasize);



err:

	return skb;
@@ -760,8 +767,8 @@ static struct sk_buff *receive_big(struct net_device *dev, 
				   struct virtnet_rq_stats *stats)

{

	struct page *page = buf;

	struct sk_buff *skb = page_to_skb(vi, rq, page, 0, len,

					  PAGE_SIZE, true);

	struct sk_buff *skb =

		page_to_skb(vi, rq, page, 0, len, PAGE_SIZE, true, 0);



	stats->bytes += len - vi->hdr_len;

	if (unlikely(!skb))
@@ -793,6 +800,7 @@ static struct sk_buff *receive_mergeable(struct net_device *dev, 
	unsigned int truesize;

	unsigned int headroom = mergeable_ctx_to_headroom(ctx);

	int err;

	unsigned int metasize = 0;



	head_skb = NULL;

	stats->bytes += len - vi->hdr_len;
@@ -839,8 +847,8 @@ static struct sk_buff *receive_mergeable(struct net_device *dev, 
		data = page_address(xdp_page) + offset;

		xdp.data_hard_start = data - VIRTIO_XDP_HEADROOM + vi->hdr_len;

		xdp.data = data + vi->hdr_len;

		xdp_set_data_meta_invalid(&xdp);

		xdp.data_end = xdp.data + (len - vi->hdr_len);

		xdp.data_meta = xdp.data;

		xdp.rxq = &rq->xdp_rxq;



		act = bpf_prog_run_xdp(xdp_prog, &xdp);
@@ -848,24 +856,27 @@ static struct sk_buff *receive_mergeable(struct net_device *dev, 


		switch (act) {

		case XDP_PASS:

			metasize = xdp.data - xdp.data_meta;



			/* recalculate offset to account for any header

			 * adjustments. Note other cases do not build an

			 * skb and avoid using offset

			 * adjustments and minus the metasize to copy the

			 * metadata in page_to_skb(). Note other cases do not

			 * build an skb and avoid using offset

			 */

			offset = xdp.data -

					page_address(xdp_page) - vi->hdr_len;

			offset = xdp.data - page_address(xdp_page) -

				 vi->hdr_len - metasize;



			/* recalculate len if xdp.data or xdp.data_end were

			 * adjusted

			/* recalculate len if xdp.data, xdp.data_end or

			 * xdp.data_meta were adjusted

			 */

			len = xdp.data_end - xdp.data + vi->hdr_len;

			len = xdp.data_end - xdp.data + vi->hdr_len + metasize;

			/* We can only create skb based on xdp_page. */

			if (unlikely(xdp_page != page)) {

				rcu_read_unlock();

				put_page(page);

				head_skb = page_to_skb(vi, rq, xdp_page,

						       offset, len,

						       PAGE_SIZE, false);

				head_skb = page_to_skb(vi, rq, xdp_page, offset,

						       len, PAGE_SIZE, false,

						       metasize);

				return head_skb;

			}

			break;
@@ -921,7 +932,8 @@ static struct sk_buff *receive_mergeable(struct net_device *dev, 
		goto err_skb;

	}



	head_skb = page_to_skb(vi, rq, page, offset, len, truesize, !xdp_prog);

	head_skb = page_to_skb(vi, rq, page, offset, len, truesize, !xdp_prog,

			       metasize);

	curr_skb = head_skb;



	if (unlikely(!curr_skb))

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