selftests/bpf: Add missing files required by test_bpftool.sh for installing

test_bpftool.sh relies on bpftool and test_bpftool.py.

'make install' will install bpftool to INSTALL_PATH/bpf/bpftool, and
export it to PATH so that it can be used after installing.

Signed-off-by: Li Zhijian <lizhijian@cn.fujitsu.com>
Signed-off-by: Alexei Starovoitov <ast@kernel.org>
Link: https://lore.kernel.org/bpf/20210820015556.23276-5-lizhijian@cn.fujitsu.com

selftests/bpf: Add default bpftool built by selftests to PATH

For 'make run_tests':
selftests will build bpftool into tools/testing/selftests/bpf/tools/sbin/bpftool
by default.

==================
root@lkp-skl-d01 /opt/rootfs/v5.14-rc4# make -C tools/testing/selftests/bpf run_tests
make: Entering directory '/opt/rootfs/v5.14-rc4/tools/testing/selftests/bpf'
MKDIR include
MKDIR libbpf
MKDIR bpftool
[...]
GEN /opt/rootfs/v5.14-rc4/tools/testing/selftests/bpf/tools/build/bpftool/profiler.skel.h
CC /opt/rootfs/v5.14-rc4/tools/testing/selftests/bpf/tools/build/bpftool/prog.o
GEN /opt/rootfs/v5.14-rc4/tools/testing/selftests/bpf/tools/build/bpftool/pid_iter.skel.h
CC /opt/rootfs/v5.14-rc4/tools/testing/selftests/bpf/tools/build/bpftool/pids.o
LINK /opt/rootfs/v5.14-rc4/tools/testing/selftests/bpf/tools/build/bpftool/bpftool
INSTALL bpftool
GEN vmlinux.h
[...]
# test_feature_dev_json (test_bpftool.TestBpftool) ... ERROR
# test_feature_kernel (test_bpftool.TestBpftool) ... ERROR
# test_feature_kernel_full (test_bpftool.TestBpftool) ... ERROR
# test_feature_kernel_full_vs_not_full (test_bpftool.TestBpftool) ... ERROR
# test_feature_macros (test_bpftool.TestBpftool) ... Error: bug: failed to retrieve CAP_BPF status: Invalid argument
# ERROR
#
# ======================================================================
# ERROR: test_feature_dev_json (test_bpftool.TestBpftool)
# ----------------------------------------------------------------------
# Traceback (most recent call last):
# File "/opt/rootfs/v5.14-rc4/tools/testing/selftests/bpf/test_bpftool.py", line 57, in wrapper
# return f(*args, iface, **kwargs)
# File "/opt/rootfs/v5.14-rc4/tools/testing/selftests/bpf/test_bpftool.py", line 82, in test_feature_dev_json
# res = bpftool_json(["feature", "probe", "dev", iface])
# File "/opt/rootfs/v5.14-rc4/tools/testing/selftests/bpf/test_bpftool.py", line 42, in bpftool_json
# res = _bpftool(args)
# File "/opt/rootfs/v5.14-rc4/tools/testing/selftests/bpf/test_bpftool.py", line 34, in _bpftool
# return subprocess.check_output(_args)
# File "/usr/lib/python3.7/subprocess.py", line 395, in check_output
# **kwargs).stdout
# File "/usr/lib/python3.7/subprocess.py", line 487, in run
# output=stdout, stderr=stderr)
# subprocess.CalledProcessError: Command '['bpftool', '-j', 'feature', 'probe', 'dev', 'dummy0']' returned non-zero exit status 255.
#
==================

Signed-off-by: Li Zhijian <lizhijian@cn.fujitsu.com>
Signed-off-by: Alexei Starovoitov <ast@kernel.org>
Acked-by: Song Liu <songliubraving@fb.com>
Link: https://lore.kernel.org/bpf/20210820015556.23276-4-lizhijian@cn.fujitsu.com

selftests/bpf: Add test for "bpftool feature" command

Add Python module with tests for "bpftool feature" command, which mainly
checks whether the "full" option is working properly.

Signed-off-by: Michal Rostecki <mrostecki@opensuse.org>
Signed-off-by: Daniel Borkmann <daniel@iogearbox.net>
Reviewed-by: Quentin Monnet <quentin@isovalent.com>
Link: https://lore.kernel.org/bpf/20200226165941.6379-6-mrostecki@opensuse.org