selftests/bpf: fix lots of silly mistakes pointed out by compiler

Once we enable -Wall for BPF sources, compiler will complain about lots
of unused variables, variables that are set but never read, etc.

Fix all these issues first before enabling -Wall in Makefile.

Signed-off-by: Andrii Nakryiko <andrii@kernel.org>
Link: https://lore.kernel.org/r/20230309054015.4068562-4-andrii@kernel.org
Signed-off-by: Alexei Starovoitov <ast@kernel.org>

bpf: Enable bpf_{g,s}etsockopt in BPF_CGROUP_UDP{4,6}_RECVMSG

Those hooks run as BPF_CGROUP_RUN_SA_PROG_LOCK and operate on a locked socket.

Note that we could remove the switch for prog->expected_attach_type altogether
since all current sock_addr attach types are covered. However, it makes sense
to keep it as a safe-guard in case new sock_addr attach types are added that
might not operate on a locked socket. Therefore, avoid to let this slip through.

Signed-off-by: Stanislav Fomichev <sdf@google.com>
Signed-off-by: Daniel Borkmann <daniel@iogearbox.net>
Link: https://lore.kernel.org/bpf/20210127232853.3753823-5-sdf@google.com

selftests/bpf: Rewrite recvmsg{4,6} asm progs to c in test_sock_addr

I'll extend them in the next patch. It's easier to work with C
than with asm.

Signed-off-by: Stanislav Fomichev <sdf@google.com>
Signed-off-by: Daniel Borkmann <daniel@iogearbox.net>
Link: https://lore.kernel.org/bpf/20210127232853.3753823-4-sdf@google.com