[PATCH bpf-next v7 2/5] bpf: Expose bpf_get_socket_cookie to tracing programs

[Florent Revest]

This needs a new helper that:
- can work in a sleepable context (using sock_gen_cookie)
- takes a struct sock pointer and checks that it's not NULL

Signed-off-by: Florent Revest <rev...@chromium.org>
Acked-by: KP Singh <kpsi...@kernel.org>
---
 include/linux/bpf.h            |  1 +
 include/uapi/linux/bpf.h       |  8 ++++++++
 kernel/trace/bpf_trace.c       |  2 ++
 net/core/filter.c              | 12 ++++++++++++
 tools/include/uapi/linux/bpf.h |  8 ++++++++
 5 files changed, 31 insertions(+)

diff --git a/include/linux/bpf.h b/include/linux/bpf.h
index 321966fc35db..d212ae7d9731 100644
--- a/include/linux/bpf.h
+++ b/include/linux/bpf.h
@@ -1888,6 +1888,7 @@ extern const struct bpf_func_proto bpf_per_cpu_ptr_proto;
 extern const struct bpf_func_proto bpf_this_cpu_ptr_proto;
 extern const struct bpf_func_proto bpf_ktime_get_coarse_ns_proto;
 extern const struct bpf_func_proto bpf_sock_from_file_proto;
+extern const struct bpf_func_proto bpf_get_socket_ptr_cookie_proto;
 
 const struct bpf_func_proto *bpf_tracing_func_proto(
        enum bpf_func_id func_id, const struct bpf_prog *prog);
diff --git a/include/uapi/linux/bpf.h b/include/uapi/linux/bpf.h
index 0b735c2729b2..a8d9ad543300 100644
--- a/include/uapi/linux/bpf.h
+++ b/include/uapi/linux/bpf.h
@@ -1673,6 +1673,14 @@ union bpf_attr {
  *     Return
  *             A 8-byte long unique number.
  *
+ * u64 bpf_get_socket_cookie(struct sock *sk)
+ *     Description
+ *             Equivalent to **bpf_get_socket_cookie**\ () helper that accepts
+ *             *sk*, but gets socket from a BTF **struct sock**. This helper
+ *             also works for sleepable programs.
+ *     Return
+ *             A 8-byte long unique number or 0 if *sk* is NULL.
+ *
  * u32 bpf_get_socket_uid(struct sk_buff *skb)
  *     Return
  *             The owner UID of the socket associated to *skb*. If the socket
diff --git a/kernel/trace/bpf_trace.c b/kernel/trace/bpf_trace.c
index 6c0018abe68a..845b2168e006 100644
--- a/kernel/trace/bpf_trace.c
+++ b/kernel/trace/bpf_trace.c
@@ -1760,6 +1760,8 @@ tracing_prog_func_proto(enum bpf_func_id func_id, const 
struct bpf_prog *prog)
                return &bpf_sk_storage_delete_tracing_proto;
        case BPF_FUNC_sock_from_file:
                return &bpf_sock_from_file_proto;
+       case BPF_FUNC_get_socket_cookie:
+               return &bpf_get_socket_ptr_cookie_proto;
 #endif
        case BPF_FUNC_seq_printf:
                return prog->expected_attach_type == BPF_TRACE_ITER ?
diff --git a/net/core/filter.c b/net/core/filter.c
index e15d4741719a..57aaed478362 100644
--- a/net/core/filter.c
+++ b/net/core/filter.c
@@ -4631,6 +4631,18 @@ static const struct bpf_func_proto 
bpf_get_socket_cookie_sock_proto = {
        .arg1_type      = ARG_PTR_TO_CTX,
 };
 
+BPF_CALL_1(bpf_get_socket_ptr_cookie, struct sock *, sk)
+{
+       return sk ? sock_gen_cookie(sk) : 0;
+}
+
+const struct bpf_func_proto bpf_get_socket_ptr_cookie_proto = {
+       .func           = bpf_get_socket_ptr_cookie,
+       .gpl_only       = false,
+       .ret_type       = RET_INTEGER,
+       .arg1_type      = ARG_PTR_TO_BTF_ID_SOCK_COMMON,
+};
+
 BPF_CALL_1(bpf_get_socket_cookie_sock_ops, struct bpf_sock_ops_kern *, ctx)
 {
        return __sock_gen_cookie(ctx->sk);
diff --git a/tools/include/uapi/linux/bpf.h b/tools/include/uapi/linux/bpf.h
index 0b735c2729b2..a8d9ad543300 100644
--- a/tools/include/uapi/linux/bpf.h
+++ b/tools/include/uapi/linux/bpf.h
@@ -1673,6 +1673,14 @@ union bpf_attr {
  *     Return
  *             A 8-byte long unique number.
  *
+ * u64 bpf_get_socket_cookie(struct sock *sk)
+ *     Description
+ *             Equivalent to **bpf_get_socket_cookie**\ () helper that accepts
+ *             *sk*, but gets socket from a BTF **struct sock**. This helper
+ *             also works for sleepable programs.
+ *     Return
+ *             A 8-byte long unique number or 0 if *sk* is NULL.
+ *
  * u32 bpf_get_socket_uid(struct sk_buff *skb)
  *     Return
  *             The owner UID of the socket associated to *skb*. If the socket
-- 
2.30.0.478.g8a0d178c01-goog