bpf: Add bpf_skc_to_unix_sock() helper
The helper is used in tracing programs to cast a socket
pointer to a unix_sock pointer.
The return value could be NULL if the casting is illegal.
Suggested-by: Yonghong Song <yhs@fb.com>
Signed-off-by: Hengqi Chen <hengqi.chen@gmail.com>
Signed-off-by: Alexei Starovoitov <ast@kernel.org>
Acked-by: Song Liu <songliubraving@fb.com>
Link: https://lore.kernel.org/bpf/20211021134752.1223426-2-hengqi.chen@gmail.com
diff --git a/kernel/trace/bpf_trace.c b/kernel/trace/bpf_trace.c
index 6b31538..cbcd0d6 100644
--- a/kernel/trace/bpf_trace.c
+++ b/kernel/trace/bpf_trace.c
@@ -1608,6 +1608,8 @@ tracing_prog_func_proto(enum bpf_func_id func_id, const struct bpf_prog *prog)
return &bpf_skc_to_tcp_request_sock_proto;
case BPF_FUNC_skc_to_udp6_sock:
return &bpf_skc_to_udp6_sock_proto;
+ case BPF_FUNC_skc_to_unix_sock:
+ return &bpf_skc_to_unix_sock_proto;
case BPF_FUNC_sk_storage_get:
return &bpf_sk_storage_get_tracing_proto;
case BPF_FUNC_sk_storage_delete: