On Mon, Feb 24, 2025 at 11:29 PM Marcus Wichelmann
[off-list ref] wrote:
When the XDP metadata area was used, it is expected that the same
metadata can also be accessed from TC, as can be read in the description
of the bpf_xdp_adjust_meta helper function. In the tun driver, this was
not yet implemented.
To make this work, the skb that is being built on XDP_PASS should know
of the current size of the metadata area. This is ensured by adding
calls to skb_metadata_set. For the tun_xdp_one code path, an additional
check is necessary to handle the case where the externally initialized
xdp_buff has no metadata support (xdp->data_meta == xdp->data + 1).
More information about this feature can be found in the commit message
of commit de8f3a83b0a0 ("bpf: add meta pointer for direct access").
Signed-off-by: Marcus Wichelmann <redacted>
Acked-by: Jason Wang <redacted>
Thanks