libbpf: Move BPF_SEQ_PRINTF and BPF_SNPRINTF to bpf_helpers.h

These macros are convenient wrappers around the bpf_seq_printf and
bpf_snprintf helpers. They are currently provided by bpf_tracing.h which
targets low level tracing primitives. bpf_helpers.h is a better fit.

The __bpf_narg and __bpf_apply are needed in both files and provided
twice. __bpf_empty isn't used anywhere and is removed from bpf_tracing.h

Reported-by: Andrii Nakryiko <andrii@kernel.org>
Signed-off-by: Florent Revest <revest@chromium.org>
Signed-off-by: Andrii Nakryiko <andrii@kernel.org>
Link: https://lore.kernel.org/bpf/20210526164643.2881368-1-revest@chromium.org

samples/bpf, selftests/bpf: Use bpf_probe_read_kernel

A handful of samples and selftests fail to build on s390, because
after commit 0ebeea8ca8a4 ("bpf: Restrict bpf_probe_read{, str}()
only to archs where they work") bpf_probe_read is not available
anymore.

Fix by using bpf_probe_read_kernel.

Signed-off-by: Ilya Leoshkevich <iii@linux.ibm.com>
Signed-off-by: Alexei Starovoitov <ast@kernel.org>
Link: https://lore.kernel.org/bpf/20200720114806.88823-1-iii@linux.ibm.com

selftests/bpf: Fix merge conflict resolution

Remove double definition of structs.

Fixes: 71930d61025e ("Merge git://git.kernel.org/pub/scm/linux/kernel/git/netdev/net")
Signed-off-by: Alexei Starovoitov <ast@kernel.org>

selftests/bpf: Refactor some net macros to bpf_tracing_net.h

Refactor bpf_iter_ipv6_route.c and bpf_iter_netlink.c
so net macros, originally from various include/linux header
files, are moved to a new header file
bpf_tracing_net.h. The goal is to improve reuse so
networking tracing programs do not need to
copy these macros every time they use them.

Signed-off-by: Yonghong Song <yhs@fb.com>
Signed-off-by: Alexei Starovoitov <ast@kernel.org>
Acked-by: Andrii Nakryiko <andriin@fb.com>
Acked-by: Martin KaFai Lau <kafai@fb.com>
Link: https://lore.kernel.org/bpf/20200623230817.3988962-1-yhs@fb.com

selftests/bpf: Move newer bpf_iter_* type redefining to a new header file

Commit b9f4c01f3e0b ("selftest/bpf: Make bpf_iter selftest
compilable against old vmlinux.h") and Commit dda18a5c0b75
("selftests/bpf: Convert bpf_iter_test_kern{3, 4}.c to define
own bpf_iter_meta") redefined newly introduced types
in bpf programs so the bpf program can still compile
properly with old kernels although loading may fail.

Since this patch set introduced new types and the same
workaround is needed, so let us move the workaround
to a separate header file so they do not clutter
bpf programs.

Signed-off-by: Yonghong Song <yhs@fb.com>
Signed-off-by: Alexei Starovoitov <ast@kernel.org>
Acked-by: Andrii Nakryiko <andriin@fb.com>
Acked-by: Martin KaFai Lau <kafai@fb.com>
Link: https://lore.kernel.org/bpf/20200623230816.3988656-1-yhs@fb.com

libbpf: Fix CO-RE relocs against .text section

bpf_object__find_program_by_title(), used by CO-RE relocation code, doesn't
return .text "BPF program", if it is a function storage for sub-programs.
Because of that, any CO-RE relocation in helper non-inlined functions will
fail. Fix this by searching for .text-corresponding BPF program manually.

Adjust one of bpf_iter selftest to exhibit this pattern.

Fixes: ddc7c3042614 ("libbpf: implement BPF CO-RE offset relocation algorithm")
Reported-by: Yonghong Song <yhs@fb.com>
Signed-off-by: Andrii Nakryiko <andriin@fb.com>
Signed-off-by: Yonghong Song <yhs@fb.com>
Signed-off-by: Alexei Starovoitov <ast@kernel.org>
Acked-by: Yonghong Song <yhs@fb.com>
Link: https://lore.kernel.org/bpf/20200619230423.691274-1-andriin@fb.com

selftest/bpf: Make bpf_iter selftest compilable against old vmlinux.h

It's good to be able to compile bpf_iter selftest even on systems that don't
have the very latest vmlinux.h, e.g., for libbpf tests against older kernels in
Travis CI. To that extent, re-define bpf_iter_meta and corresponding bpf_iter
context structs in each selftest. To avoid type clashes with vmlinux.h, rename
vmlinux.h's definitions to get them out of the way.

Signed-off-by: Andrii Nakryiko <andriin@fb.com>
Signed-off-by: Alexei Starovoitov <ast@kernel.org>
Acked-by: Yonghong Song <yhs@fb.com>
Acked-by: Jesper Dangaard Brouer <brouer@redhat.com>
Link: https://lore.kernel.org/bpf/20200518234516.3915052-1-andriin@fb.com

tools/bpf: selftests: Add iterator programs for ipv6_route and netlink

Two bpf programs are added in this patch for netlink and ipv6_route
target. On my VM, I am able to achieve identical
results compared to /proc/net/netlink and /proc/net/ipv6_route.

$ cat /proc/net/netlink
sk Eth Pid Groups Rmem Wmem Dump Locks Drops Inode
000000002c42d58b 0 0 00000000 0 0 0 2 0 7
00000000a4e8b5e1 0 1 00000551 0 0 0 2 0 18719
00000000e1b1c195 4 0 00000000 0 0 0 2 0 16422
000000007e6b29f9 6 0 00000000 0 0 0 2 0 16424
....
00000000159a170d 15 1862 00000002 0 0 0 2 0 1886
000000009aca4bc9 15 3918224839 00000002 0 0 0 2 0 19076
00000000d0ab31d2 15 1 00000002 0 0 0 2 0 18683
000000008398fb08 16 0 00000000 0 0 0 2 0 27
$ cat /sys/fs/bpf/my_netlink
sk Eth Pid Groups Rmem Wmem Dump Locks Drops Inode
000000002c42d58b 0 0 00000000 0 0 0 2 0 7
00000000a4e8b5e1 0 1 00000551 0 0 0 2 0 18719
00000000e1b1c195 4 0 00000000 0 0 0 2 0 16422
000000007e6b29f9 6 0 00000000 0 0 0 2 0 16424
....
00000000159a170d 15 1862 00000002 0 0 0 2 0 1886
000000009aca4bc9 15 3918224839 00000002 0 0 0 2 0 19076
00000000d0ab31d2 15 1 00000002 0 0 0 2 0 18683
000000008398fb08 16 0 00000000 0 0 0 2 0 27

$ cat /proc/net/ipv6_route
fe800000000000000000000000000000 40 00000000000000000000000000000000 00 00000000000000000000000000000000 00000100 00000001 00000000 00000001 eth0
00000000000000000000000000000000 00 00000000000000000000000000000000 00 00000000000000000000000000000000 ffffffff 00000001 00000000 00200200 lo
00000000000000000000000000000001 80 00000000000000000000000000000000 00 00000000000000000000000000000000 00000000 00000003 00000000 80200001 lo
fe80000000000000c04b03fffe7827ce 80 00000000000000000000000000000000 00 00000000000000000000000000000000 00000000 00000002 00000000 80200001 eth0
ff000000000000000000000000000000 08 00000000000000000000000000000000 00 00000000000000000000000000000000 00000100 00000003 00000000 00000001 eth0
00000000000000000000000000000000 00 00000000000000000000000000000000 00 00000000000000000000000000000000 ffffffff 00000001 00000000 00200200 lo
$ cat /sys/fs/bpf/my_ipv6_route
fe800000000000000000000000000000 40 00000000000000000000000000000000 00 00000000000000000000000000000000 00000100 00000001 00000000 00000001 eth0
00000000000000000000000000000000 00 00000000000000000000000000000000 00 00000000000000000000000000000000 ffffffff 00000001 00000000 00200200 lo
00000000000000000000000000000001 80 00000000000000000000000000000000 00 00000000000000000000000000000000 00000000 00000003 00000000 80200001 lo
fe80000000000000c04b03fffe7827ce 80 00000000000000000000000000000000 00 00000000000000000000000000000000 00000000 00000002 00000000 80200001 eth0
ff000000000000000000000000000000 08 00000000000000000000000000000000 00 00000000000000000000000000000000 00000100 00000003 00000000 00000001 eth0
00000000000000000000000000000000 00 00000000000000000000000000000000 00 00000000000000000000000000000000 ffffffff 00000001 00000000 00200200 lo

Signed-off-by: Yonghong Song <yhs@fb.com>
Signed-off-by: Alexei Starovoitov <ast@kernel.org>
Acked-by: Andrii Nakryiko <andriin@fb.com>
Link: https://lore.kernel.org/bpf/20200509175921.2477493-1-yhs@fb.com