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0c90f2243e
bpftool uses hexadecimal values when it dumps map contents:
# bpftool map dump id 1337
key: ff 13 37 ff value: a1 b2 c3 d4 ff ff ff ff
Found 1 element
In order to lookup or update values with bpftool, the natural reflex is
then to copy and paste the values to the command line, and to try to run
something like:
# bpftool map update id 1337 key ff 13 37 ff \
value 00 00 00 00 00 00 1a 2b
Error: error parsing byte: ff
bpftool complains, because it uses strtoul() with a 0 base to parse the
bytes, and that without a "0x" prefix, the bytes are considered as
decimal values (or even octal if they start with "0").
To feed hexadecimal values instead, one needs to add "0x" prefixes
everywhere necessary:
# bpftool map update id 1337 key 0xff 0x13 0x37 0xff \
value 0 0 0 0 0 0 0x1a 0x2b
To make it easier to use hexadecimal values, add an optional "hex"
keyword to put after "key" or "value" to tell bpftool to consider the
digits as hexadecimal. We can now do:
# bpftool map update id 1337 key hex ff 13 37 ff \
value hex 0 0 0 0 0 0 1a 2b
Without the "hex" keyword, the bytes are still parsed according to
normal integer notation (decimal if no prefix, or hexadecimal or octal
if "0x" or "0" prefix is used, respectively).
The patch also add related documentation and bash completion for the
"hex" keyword.
Suggested-by: Daniel Borkmann <daniel@iogearbox.net>
Suggested-by: David Beckett <david.beckett@netronome.com>
Signed-off-by: Quentin Monnet <quentin.monnet@netronome.com>
Acked-by: Jakub Kicinski <jakub.kicinski@netronome.com>
Signed-off-by: Daniel Borkmann <daniel@iogearbox.net>
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.
See Documentation/00-INDEX for a list of what is contained in each file.
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.