On 25/01/2023 01.33, Lorenzo Bianconi wrote:
Check if the destination device implements ndo_xdp_xmit callback relying
on NETDEV_XDP_ACT_NDO_XMIT flags. Moreover, check if the destination device
supports XDP non-linear frame in __xdp_enqueue and is_valid_dst routines.
This patch allows to perform XDP_REDIRECT on non-linear XDP buffers.
Co-developed-by: Kumar Kartikeya Dwivedi <memxor@xxxxxxxxx>
Signed-off-by: Kumar Kartikeya Dwivedi <memxor@xxxxxxxxx>
Signed-off-by: Lorenzo Bianconi <lorenzo@xxxxxxxxxx>
---
kernel/bpf/devmap.c | 16 +++++++++++++---
net/core/filter.c | 13 +++++--------
2 files changed, 18 insertions(+), 11 deletions(-)
LGTM
Acked-by: Jesper Dangaard Brouer <brouer@xxxxxxxxxx>
diff --git a/kernel/bpf/devmap.c b/kernel/bpf/devmap.c
index d01e4c55b376..2675fefc6cb6 100644
--- a/kernel/bpf/devmap.c
+++ b/kernel/bpf/devmap.c
@@ -474,7 +474,11 @@ static inline int __xdp_enqueue(struct net_device *dev, struct xdp_frame *xdpf,
{
int err;
- if (!dev->netdev_ops->ndo_xdp_xmit)
+ if (!(dev->xdp_features & NETDEV_XDP_ACT_NDO_XMIT))
+ return -EOPNOTSUPP;
Good: dev->netdev_ops and dev->xdp_features are on same cacheline.
This means dev->netdev_ops will be hot, once we need to deref
netdev_ops->ndo_xdp_xmit, which only happens as part of bulking towards
driver.
+
+ if (unlikely(!(dev->xdp_features & NETDEV_XDP_ACT_NDO_XMIT_SG) &&
+ xdp_frame_has_frags(xdpf)))
Good: xdp_frame_has_frags() look at xdpf->flags and avoids deref of
shared_info area.
return -EOPNOTSUPP;
err = xdp_ok_fwd_dev(dev, xdp_get_frame_len(xdpf));
@@ -532,8 +536,14 @@ int dev_map_enqueue(struct bpf_dtab_netdev *dst, struct xdp_frame *xdpf,
static bool is_valid_dst(struct bpf_dtab_netdev *obj, struct xdp_frame *xdpf)
{
- if (!obj ||
- !obj->dev->netdev_ops->ndo_xdp_xmit)
+ if (!obj)
+ return false;
+
+ if (!(obj->dev->xdp_features & NETDEV_XDP_ACT_NDO_XMIT))
+ return false;
+
+ if (unlikely(!(obj->dev->xdp_features & NETDEV_XDP_ACT_NDO_XMIT_SG) &&
+ xdp_frame_has_frags(xdpf)))
return false;
if (xdp_ok_fwd_dev(obj->dev, xdp_get_frame_len(xdpf)))
diff --git a/net/core/filter.c b/net/core/filter.c
index ed08dbf10338..aeebe21a7eff 100644
--- a/net/core/filter.c
+++ b/net/core/filter.c
@@ -4314,16 +4314,13 @@ int xdp_do_redirect(struct net_device *dev, struct xdp_buff *xdp,
struct bpf_redirect_info *ri = this_cpu_ptr(&bpf_redirect_info);
enum bpf_map_type map_type = ri->map_type;
- /* XDP_REDIRECT is not fully supported yet for xdp frags since
- * not all XDP capable drivers can map non-linear xdp_frame in
- * ndo_xdp_xmit.
- */
- if (unlikely(xdp_buff_has_frags(xdp) &&
- map_type != BPF_MAP_TYPE_CPUMAP))
- return -EOPNOTSUPP;
Nice to see this limitation being lifted :-)
+ if (map_type == BPF_MAP_TYPE_XSKMAP) {
+ /* XDP_REDIRECT is not supported AF_XDP yet. */
+ if (unlikely(xdp_buff_has_frags(xdp)))
+ return -EOPNOTSUPP;
- if (map_type == BPF_MAP_TYPE_XSKMAP)
return __xdp_do_redirect_xsk(ri, dev, xdp, xdp_prog);
+ }
return __xdp_do_redirect_frame(ri, dev, xdp_convert_buff_to_frame(xdp),
xdp_prog);
