linux-toradex.git/samples/bpf, branch v5.15-rc5

samples/bpf: Relicense bpf_insn.h as GPL-2.0-only OR BSD-2-Clause

2021-09-29T14:03:55+00:00

libbpf and bpftool have been dual-licensed to facilitate inclusion in software
that is not compatible with GPL2-only (ie: Apache2), but the samples are still
GPL2-only.

Given these files are samples, they get naturally copied around. For example,
it is the case for samples/bpf/bpf_insn.h which was copied into the systemd
tree: https://github.com/systemd/systemd/blob/main/src/shared/linux/bpf_insn.h

Some more context on systemd's needs specifically:

  Most of systemd is (L)GPL2-or-later, which means there is no perceived
  incompatibility with Apache2 software and can thus be linked with
  OpenSSL 3.0. But given this GPL2-only header is included this is currently
  not possible. Dual-licensing this header solves this problem for us as we
  are scoping a move to OpenSSL 3.0, see:

  https://lists.freedesktop.org/archives/systemd-devel/2021-September/046882.html

Dual-license this header as GPL-2.0-only OR BSD-2-Clause to follow the same
licensing used by libbpf and bpftool:

  1bc38b8ff6cc ("libbpf: relicense libbpf as LGPL-2.1 OR BSD-2-Clause")
  907b22365115 ("tools: bpftool: dual license all files")

Signed-off-by: Luca Boccassi 
Signed-off-by: Daniel Borkmann 
Acked-by: Simon Horman 
Acked-by: Daniel Mack 
Acked-by: Josef Bacik 
Acked-by: Joe Stringer 
Acked-by: Chenbo Feng 
Acked-by: Björn Töpel 
Acked-by: Magnus Karlsson 
Acked-by: Brendan Jackman 
Acked-by: Daniel Borkmann 
Acked-by: Alexei Starovoitov 
Link: https://lore.kernel.org/bpf/20210923000540.47344-1-luca.boccassi@gmail.com

samples: bpf: Fix vmlinux.h generation for XDP samples

2021-09-29T00:21:35+00:00

Generate vmlinux.h only from the in-tree vmlinux, and remove enum
declarations that would cause a build failure in case of version
mismatches.

There are now two options when building the samples:
1. Compile the kernel to use in-tree vmlinux for vmlinux.h
2. Override VMLINUX_BTF for samples using something like this:
   make VMLINUX_BTF=/sys/kernel/btf/vmlinux -C samples/bpf

This change was tested with relative builds, e.g. cases like:
 * make O=build -C samples/bpf
 * make KBUILD_OUTPUT=build -C samples/bpf
 * make -C samples/bpf
 * cd samples/bpf && make

When a suitable VMLINUX_BTF is not found, the following message is
printed:
/home/kkd/src/linux/samples/bpf/Makefile:333: *** Cannot find a vmlinux
for VMLINUX_BTF at any of "  ./vmlinux", build the kernel or set
VMLINUX_BTF variable.  Stop.

Fixes: 384b6b3bbf0d (samples: bpf: Add vmlinux.h generation support)
Signed-off-by: Kumar Kartikeya Dwivedi 
Signed-off-by: Andrii Nakryiko 
Acked-by: Toke Høiland-Jørgensen 
Link: https://lore.kernel.org/bpf/20210928054608.1799021-1-memxor@gmail.com

samples: bpf: Fix uninitialized variable in xdp_redirect_cpu

2021-08-26T19:09:20+00:00

While at it, also improve help output when CPU number is greater than
possible.

Fixes: e531a220cc59 ("samples: bpf: Convert xdp_redirect_cpu to XDP samples helper")
Signed-off-by: Kumar Kartikeya Dwivedi 
Signed-off-by: Alexei Starovoitov 
Link: https://lore.kernel.org/bpf/20210826120910.454081-1-memxor@gmail.com

samples: bpf: Convert xdp_redirect_map_multi to XDP samples helper

2021-08-24T21:48:42+00:00

Use the libbpf skeleton facility and other utilities provided by XDP
samples helper. Also adapt to change of type of mac address map, so that
no resizing is required.

Add a new flag for sample mask that skips priting the
from_device->to_device heading for each line, as xdp_redirect_map_multi
may have two devices but the flow of data may be bidirectional, so the
output would be confusing.

Signed-off-by: Kumar Kartikeya Dwivedi 
Signed-off-by: Alexei Starovoitov 
Link: https://lore.kernel.org/bpf/20210821002010.845777-23-memxor@gmail.com

samples: bpf: Convert xdp_redirect_map_multi_kern.o to XDP samples helper

2021-08-24T21:48:42+00:00

One of the notable changes is using a BPF_MAP_TYPE_HASH instead of array
map to store mac addresses of devices, as the resizing behavior was
based on max_ifindex, which unecessarily maximized the capacity of map
beyond what was needed.

Signed-off-by: Kumar Kartikeya Dwivedi 
Signed-off-by: Alexei Starovoitov 
Link: https://lore.kernel.org/bpf/20210821002010.845777-22-memxor@gmail.com

samples: bpf: Convert xdp_redirect_map to XDP samples helper

2021-08-24T21:48:42+00:00

Use the libbpf skeleton facility and other utilities provided by XDP
samples helper.

Since get_mac_addr is already provided by XDP samples helper, we drop
it. Also convert to XDP samples helper similar to prior samples to
minimize duplication of code.

Signed-off-by: Kumar Kartikeya Dwivedi 
Signed-off-by: Alexei Starovoitov 
Link: https://lore.kernel.org/bpf/20210821002010.845777-21-memxor@gmail.com

samples: bpf: Convert xdp_redirect_map_kern.o to XDP samples helper

2021-08-24T21:48:42+00:00

Also update it to use consistent SEC("xdp") and SEC("xdp_devmap")
naming, and use global variable instead of BPF map for copying the mac
address.

Signed-off-by: Kumar Kartikeya Dwivedi 
Signed-off-by: Alexei Starovoitov 
Link: https://lore.kernel.org/bpf/20210821002010.845777-20-memxor@gmail.com

samples: bpf: Convert xdp_redirect_cpu to XDP samples helper

2021-08-24T21:48:42+00:00

Use the libbpf skeleton facility and other utilities provided by XDP
samples helper.

Similar to xdp_monitor, xdp_redirect_cpu was quite featureful except a
few minor omissions (e.g. redirect errno reporting). All of these have
been moved to XDP samples helper, hence drop the unneeded code and
convert to usage of helpers provided by it.

One of the important changes here is dropping of mprog-disable option,
as we make that the default. Also, we support built-in programs for some
common actions on the packet when it reaches kthread (pass, drop,
redirect to device). If the user still needs to install a custom
program, they can still supply a BPF object, however the program should
be suitably tagged with SEC("xdp_cpumap") annotation so that the
expected attach type is correct when updating our cpumap map element.

Signed-off-by: Kumar Kartikeya Dwivedi 
Signed-off-by: Alexei Starovoitov 
Link: https://lore.kernel.org/bpf/20210821002010.845777-19-memxor@gmail.com

samples: bpf: Convert xdp_redirect_cpu_kern.o to XDP samples helper

2021-08-24T21:48:42+00:00

Similar to xdp_monitor_kern, a lot of these BPF programs have been
reimplemented properly consolidating missing features from other XDP
samples. Hence, drop the unneeded code and rename to .bpf.c suffix.

Signed-off-by: Kumar Kartikeya Dwivedi 
Signed-off-by: Alexei Starovoitov 
Link: https://lore.kernel.org/bpf/20210821002010.845777-18-memxor@gmail.com

samples: bpf: Convert xdp_redirect to XDP samples helper

2021-08-24T21:48:42+00:00

Use the libbpf skeleton facility and other utilities provided by XDP
samples helper.

One important note:
The XDP samples helper handles ownership of installed XDP programs on
devices, including responding to SIGINT and SIGTERM, so drop the code
here and use the helpers we provide going forward for all xdp_redirect*
conversions.

Signed-off-by: Kumar Kartikeya Dwivedi 
Signed-off-by: Alexei Starovoitov 
Link: https://lore.kernel.org/bpf/20210821002010.845777-17-memxor@gmail.com