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Jesper Dangaard Brouer 36e04a2d78 samples/bpf: xdp2skb_meta shows transferring info from XDP to SKB
Creating a bpf sample that shows howto use the XDP 'data_meta'
infrastructure, created by Daniel Borkmann.  Very few drivers support
this feature, but I wanted a functional sample to begin with, when
working on adding driver support.

XDP data_meta is about creating a communication channel between BPF
programs.  This can be XDP tail-progs, but also other SKB based BPF
hooks, like in this case the TC clsact hook. In this sample I show
that XDP can store info named "mark", and TC/clsact chooses to use
this info and store it into the skb->mark.

It is a bit annoying that XDP and TC samples uses different tools/libs
when attaching their BPF hooks.  As the XDP and TC programs need to
cooperate and agree on a struct-layout, it is best/easiest if the two
programs can be contained within the same BPF restricted-C file.

As the bpf-loader, I choose to not use bpf_load.c (or libbpf), but
instead wrote a bash shell scripted named xdp2skb_meta.sh, which
demonstrate howto use the iproute cmdline tools 'tc' and 'ip' for
loading BPF programs.  To make it easy for first time users, the shell
script have command line parsing, and support --verbose and --dry-run
mode, if you just want to see/learn the tc+ip command syntax:

 # ./xdp2skb_meta.sh --dev ixgbe2 --dry-run
 # Dry-run mode: enable VERBOSE and don't call TC+IP
 tc qdisc del dev ixgbe2 clsact
 tc qdisc add dev ixgbe2 clsact
 tc filter add dev ixgbe2 ingress prio 1 handle 1 bpf da obj ./xdp2skb_meta_kern.o sec tc_mark
 # Flush XDP on device: ixgbe2
 ip link set dev ixgbe2 xdp off
 ip link set dev ixgbe2 xdp obj ./xdp2skb_meta_kern.o sec xdp_mark

Signed-off-by: Jesper Dangaard Brouer <brouer@redhat.com>
Signed-off-by: Daniel Borkmann <daniel@iogearbox.net>
2018-01-11 01:02:25 +01:00
arch s390/diag: add diag26c support for VNIC info 2018-01-02 13:52:23 -05:00
block block-throttle: avoid double charge 2017-12-20 11:10:17 -07:00
certs License cleanup: add SPDX GPL-2.0 license identifier to files with no license 2017-11-02 11:10:55 +01:00
crypto Merge branch 'linus' of git://git.kernel.org/pub/scm/linux/kernel/git/herbert/crypto-2.6 2017-12-22 12:22:48 -08:00
Documentation Merge git://git.kernel.org/pub/scm/linux/kernel/git/davem/net 2017-12-29 15:42:26 -05:00
drivers nfp: bpf: reuse verifier log for debug messages 2018-01-10 13:49:36 +01:00
firmware kbuild: remove all dummy assignments to obj- 2017-11-18 11:46:06 +09:00
fs nsfs: generalize ns_get_path() for path resolution with a task 2017-12-31 16:12:23 +01:00
include bpf: export function to write into verifier log buffer 2018-01-10 13:49:36 +01:00
init Merge branch 'x86-pti-for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip 2017-12-23 11:53:04 -08:00
ipc Rename superblock flags (MS_xyz -> SB_xyz) 2017-11-27 13:05:09 -08:00
kernel bpf: export function to write into verifier log buffer 2018-01-10 13:49:36 +01:00
lib Merge git://git.kernel.org/pub/scm/linux/kernel/git/davem/net 2017-12-22 11:16:31 -05:00
mm Merge branch 'for-linus' of git://git.kernel.dk/linux-block 2017-12-21 11:13:37 -08:00
net net: free RX queue structures 2018-01-10 12:06:17 +01:00
samples samples/bpf: xdp2skb_meta shows transferring info from XDP to SKB 2018-01-11 01:02:25 +01:00
scripts Merge branch 'locking-urgent-for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip 2017-12-15 11:44:59 -08:00
security Merge git://git.kernel.org/pub/scm/linux/kernel/git/davem/net 2017-12-16 22:11:55 -05:00
sound ALSA: hda - Fix missing COEF init for ALC225/295/299 2017-12-27 08:53:59 +01:00
tools selftests: fib_tests: Add test cases for netdev carrier change 2018-01-07 21:29:41 -05:00
usr initramfs: fix initramfs rebuilds w/ compression after disabling 2017-11-03 07:39:19 -07:00
virt KVM/ARM Fixes for v4.15, Round 2 2017-12-18 12:57:43 +01:00
.cocciconfig scripts: add Linux .cocciconfig for coccinelle 2016-07-22 12:13:39 +02:00
.get_maintainer.ignore Add hch to .get_maintainer.ignore 2015-08-21 14:30:10 -07:00
.gitattributes .gitattributes: set git diff driver for C source code files 2016-10-07 18:46:30 -07:00
.gitignore Kbuild misc updates for v4.15 2017-11-17 17:51:33 -08:00
.mailmap Add Jason Gunthorpe as co-maintainer of the RDMA stack 2017-11-17 09:36:18 -08:00
COPYING
CREDITS MAINTAINERS: update TPM driver infrastructure changes 2017-11-09 17:58:40 -08:00
Kbuild Kbuild updates for v4.15 2017-11-17 17:45:29 -08:00
Kconfig License cleanup: add SPDX GPL-2.0 license identifier to files with no license 2017-11-02 11:10:55 +01:00
MAINTAINERS batman-adv: Convert packet.h to uapi header 2017-12-21 15:35:53 -05:00
Makefile Linux 4.15-rc5 2017-12-23 20:47:16 -08:00
README README: add a new README file, pointing to the Documentation/ 2016-10-24 08:12:35 -02:00

Linux kernel
============

This file was moved to Documentation/admin-guide/README.rst

Please notice that there are several guides for kernel developers and users.
These guides can be rendered in a number of formats, like HTML and PDF.

In order to build the documentation, use ``make htmldocs`` or
``make pdfdocs``.

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.