When we update devmap element, the net_device whose ifindex is specified
in map value must support ndo_xdp_xmit callback, which is indicated by
the presence of XDP_F_REDIRECT_TARGET feature. Let's check for
this feature and return an error if device cannot be used as a redirect
target.
Moreover check the device support xdp non-linear frame in __xdp_enqueue
and is_valid_dst routines. This patch allows to perfrom 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 | 25 +++++++++++++++++++++----
net/core/filter.c | 13 +++++--------
2 files changed, 26 insertions(+), 12 deletions(-)
diff --git a/kernel/bpf/devmap.c b/kernel/bpf/devmap.c
index d01e4c55b376..16199eb5c7a6 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 & XDP_F_REDIRECT_TARGET))
+ return -EOPNOTSUPP;
+
+ if (unlikely(!(dev->xdp_features & XDP_F_FRAG_TARGET) &&
+ xdp_frame_has_frags(xdpf)))
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 & XDP_F_REDIRECT_TARGET))
+ return false;
+
+ if (unlikely(!(obj->dev->xdp_features & XDP_F_FRAG_TARGET) &&
+ xdp_frame_has_frags(xdpf)))
return false;
if (xdp_ok_fwd_dev(obj->dev, xdp_get_frame_len(xdpf)))
@@ -843,6 +853,7 @@ static struct bpf_dtab_netdev *__dev_map_alloc_node(struct net *net,
{
struct bpf_prog *prog = NULL;
struct bpf_dtab_netdev *dev;
+ int ret = -EINVAL;
dev = bpf_map_kmalloc_node(&dtab->map, sizeof(*dev),
GFP_NOWAIT | __GFP_NOWARN,
@@ -854,6 +865,12 @@ static struct bpf_dtab_netdev *__dev_map_alloc_node(struct net *net,
if (!dev->dev)
goto err_out;
+ /* Check if net_device can be used as a redirect target */
+ if (!(READ_ONCE(dev->dev->xdp_features) & XDP_F_REDIRECT_TARGET)) {
+ ret = -EOPNOTSUPP;
+ goto err_put_dev;
+ }
+
if (val->bpf_prog.fd > 0) {
prog = bpf_prog_get_type_dev(val->bpf_prog.fd,
BPF_PROG_TYPE_XDP, false);
@@ -882,7 +899,7 @@ static struct bpf_dtab_netdev *__dev_map_alloc_node(struct net *net,
dev_put(dev->dev);
err_out:
kfree(dev);
- return ERR_PTR(-EINVAL);
+ return ERR_PTR(ret);
}
static int __dev_map_update_elem(struct net *net, struct bpf_map *map,
diff --git a/net/core/filter.c b/net/core/filter.c
index 929358677183..c2bd1935b55a 100644
--- a/net/core/filter.c
+++ b/net/core/filter.c
@@ -4282,16 +4282,13 @@ 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;
+ 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);
--
2.38.1
