From: Yuya Kusakabe <yuya.kusakabe@xxxxxxxxx> [ Upstream commit 503d539a6e417b018616bf3060e0b5814fafce47 ] 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: Yuya Kusakabe <yuya.kusakabe@xxxxxxxxx> Signed-off-by: Daniel Borkmann <daniel@xxxxxxxxxxxxx> Acked-by: Jason Wang <jasowang@xxxxxxxxxx> Acked-by: Michael S. Tsirkin <mst@xxxxxxxxxx> Link: https://lore.kernel.org/bpf/20200225033212.437563-2-yuya.kusakabe@xxxxxxxxx Signed-off-by: Sasha Levin <sashal@xxxxxxxxxx> --- drivers/net/virtio_net.c | 52 ++++++++++++++++++++++++---------------- 1 file changed, 32 insertions(+), 20 deletions(-) diff --git a/drivers/net/virtio_net.c b/drivers/net/virtio_net.c index 0ef85819665c..b67460864b3c 100644 --- a/drivers/net/virtio_net.c +++ b/drivers/net/virtio_net.c @@ -376,7 +376,7 @@ 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; @@ -398,6 +398,7 @@ 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); @@ -410,6 +411,11 @@ 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; @@ -455,10 +461,6 @@ 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; @@ -649,6 +651,7 @@ 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; @@ -688,8 +691,8 @@ 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); @@ -700,6 +703,7 @@ 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++; @@ -745,6 +749,9 @@ static struct sk_buff *receive_small(struct net_device *dev, memcpy(skb_vnet_hdr(skb), buf, vi->hdr_len); } /* keep zeroed vnet hdr since packet was changed by bpf */ + if (metasize) + skb_metadata_set(skb, metasize); + err: return skb; @@ -765,8 +772,8 @@ 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)) @@ -798,6 +805,7 @@ 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; @@ -844,8 +852,8 @@ 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); @@ -853,24 +861,27 @@ 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; @@ -926,7 +937,8 @@ 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)) -- 2.30.2
