d677266755
The NIC hardware RX timestamping mechanism adds an optional tailored header before the MAC header containing packet reception time. Optional depending on RX descriptor TSIP status bit (IGC_RXDADV_STAT_TSIP). In case this bit is set driver does offset adjustments to packet data start and extracts the timestamp. The timestamp need to be extracted before invoking the XDP bpf_prog, because this area just before the packet is also accessible by XDP via data_meta context pointer (and helper bpf_xdp_adjust_meta). Thus, an XDP bpf_prog can potentially overwrite this and corrupt data that we want to extract with the new kfunc for reading the timestamp. Signed-off-by: Jesper Dangaard Brouer <brouer@redhat.com> Signed-off-by: Daniel Borkmann <daniel@iogearbox.net> Acked-by: Song Yoong Siang <yoong.siang.song@intel.com> Link: https://lore.kernel.org/bpf/168182465791.616355.2583922957423587914.stgit@firesoul
Linux kernel
============
There are several guides for kernel developers and users. These guides can
be rendered in a number of formats, like HTML and PDF. Please read
Documentation/admin-guide/README.rst first.
In order to build the documentation, use ``make htmldocs`` or
``make pdfdocs``. The formatted documentation can also be read online at:
https://www.kernel.org/doc/html/latest/
There are various text files in the Documentation/ subdirectory,
several of them using the Restructured Text markup notation.
Please read the Documentation/process/changes.rst file, as it contains the
requirements for building and running the kernel, and information about
the problems which may result by upgrading your kernel.