diff options
Diffstat (limited to 'Documentation/networking/xdp-rx-metadata.rst')
| -rw-r--r-- | Documentation/networking/xdp-rx-metadata.rst | 7 |
1 files changed, 5 insertions, 2 deletions
diff --git a/Documentation/networking/xdp-rx-metadata.rst b/Documentation/networking/xdp-rx-metadata.rst index aac63fc2d08b..25ce72af81c2 100644 --- a/Documentation/networking/xdp-rx-metadata.rst +++ b/Documentation/networking/xdp-rx-metadata.rst @@ -23,10 +23,13 @@ metadata is supported, this set will grow: An XDP program can use these kfuncs to read the metadata into stack variables for its own consumption. Or, to pass the metadata on to other consumers, an XDP program can store it into the metadata area carried -ahead of the packet. +ahead of the packet. Not all packets will necessary have the requested +metadata available in which case the driver returns ``-ENODATA``. Not all kfuncs have to be implemented by the device driver; when not -implemented, the default ones that return ``-EOPNOTSUPP`` will be used. +implemented, the default ones that return ``-EOPNOTSUPP`` will be used +to indicate the device driver have not implemented this kfunc. + Within an XDP frame, the metadata layout (accessed via ``xdp_buff``) is as follows:: |