| Message ID | 20180417065131.3632-11-tehnerd@tehnerd.com |
|---|---|
| State | Changes Requested, archived |
| Delegated to: | BPF Maintainers |
| Headers | show |
| Series | introduction of bpf_xdp_adjust_tail | expand |
On 2018年04月17日 14:51, Nikita V. Shirokov wrote: > w/ bpf_xdp_adjust_tail helper xdp's data_end pointer could be changed as > well (only "decrease" of pointer's location is going to be supported). > changing of this pointer will change packet's size. > for virtio driver we need to adjust XDP_PASS handling by recalculating > length of the packet if it was passed to the TCP/IP stack > > Signed-off-by: Nikita V. Shirokov <tehnerd@tehnerd.com> > --- > drivers/net/virtio_net.c | 7 ++++++- > 1 file changed, 6 insertions(+), 1 deletion(-) > > diff --git a/drivers/net/virtio_net.c b/drivers/net/virtio_net.c > index 7b187ec7411e..115d85f7360a 100644 > --- a/drivers/net/virtio_net.c > +++ b/drivers/net/virtio_net.c > @@ -604,6 +604,7 @@ static struct sk_buff *receive_small(struct net_device *dev, > case XDP_PASS: > /* Recalculate length in case bpf program changed it */ > delta = orig_data - xdp.data; > + len = xdp.data_end - xdp.data; > break; > case XDP_TX: > sent = __virtnet_xdp_xmit(vi, &xdp); > @@ -637,7 +638,7 @@ static struct sk_buff *receive_small(struct net_device *dev, > goto err; > } > skb_reserve(skb, headroom - delta); > - skb_put(skb, len + delta); > + skb_put(skb, len); > if (!delta) { > buf += header_offset; > memcpy(skb_vnet_hdr(skb), buf, vi->hdr_len); > @@ -752,6 +753,10 @@ static struct sk_buff *receive_mergeable(struct net_device *dev, > offset = xdp.data - > page_address(xdp_page) - vi->hdr_len; > > + /* recalculate len if xdp.data or xdp.data_end were > + * adjusted > + */ > + len = xdp.data_end - xdp.data; > /* We can only create skb based on xdp_page. */ > if (unlikely(xdp_page != page)) { > rcu_read_unlock(); Reviewed-by: Jason Wang <jasowang@redhat.com>
diff --git a/drivers/net/virtio_net.c b/drivers/net/virtio_net.c index 7b187ec7411e..115d85f7360a 100644 --- a/drivers/net/virtio_net.c +++ b/drivers/net/virtio_net.c @@ -604,6 +604,7 @@ static struct sk_buff *receive_small(struct net_device *dev, case XDP_PASS: /* Recalculate length in case bpf program changed it */ delta = orig_data - xdp.data; + len = xdp.data_end - xdp.data; break; case XDP_TX: sent = __virtnet_xdp_xmit(vi, &xdp); @@ -637,7 +638,7 @@ static struct sk_buff *receive_small(struct net_device *dev, goto err; } skb_reserve(skb, headroom - delta); - skb_put(skb, len + delta); + skb_put(skb, len); if (!delta) { buf += header_offset; memcpy(skb_vnet_hdr(skb), buf, vi->hdr_len); @@ -752,6 +753,10 @@ static struct sk_buff *receive_mergeable(struct net_device *dev, offset = xdp.data - page_address(xdp_page) - vi->hdr_len; + /* recalculate len if xdp.data or xdp.data_end were + * adjusted + */ + len = xdp.data_end - xdp.data; /* We can only create skb based on xdp_page. */ if (unlikely(xdp_page != page)) { rcu_read_unlock();
w/ bpf_xdp_adjust_tail helper xdp's data_end pointer could be changed as well (only "decrease" of pointer's location is going to be supported). changing of this pointer will change packet's size. for virtio driver we need to adjust XDP_PASS handling by recalculating length of the packet if it was passed to the TCP/IP stack Signed-off-by: Nikita V. Shirokov <tehnerd@tehnerd.com> --- drivers/net/virtio_net.c | 7 ++++++- 1 file changed, 6 insertions(+), 1 deletion(-)