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

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
......@@ -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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