Squash to "selftests/bpf: Add mptcp_subflow bpf_iter subtest"

Define mptcp_subflow_ctx() using bpf_core_cast as Martin suggested.

Signed-off-by: Geliang Tang <[email protected]>

Author: Geliang Tang

tools/testing/selftests/bpf/progs/mptcp_bpf.h

@@ -39,6 +39,16 @@ mptcp_subflow_tcp_sock(const struct mptcp_subflow_context *subflow)
 	return subflow->tcp_sock;
 }
 
+static __always_inline struct mptcp_subflow_context *
+mptcp_subflow_ctx(const struct sock *sk)
+{
+	const struct inet_connection_sock *
+		icsk = bpf_core_cast(sk, struct inet_connection_sock);
+
+	/* Use RCU on icsk_ulp_data only for sock diag code */
+	return bpf_core_cast(icsk->icsk_ulp_data, struct mptcp_subflow_context);
+}
+
 /* ksym */
 extern struct mptcp_subflow_context *
 bpf_mptcp_subflow_ctx(const struct sock *sk) __ksym;

tools/testing/selftests/bpf/progs/mptcp_bpf_iters.c

@@ -48,7 +48,7 @@ int iters_subflow(struct bpf_sockopt *ctx)
 		goto out;
 
 	/* only to check the following kfunc works */
-	subflow = bpf_mptcp_subflow_ctx(ssk);
+	subflow = mptcp_subflow_ctx(ssk);
 	if (!subflow || subflow->token != msk->token)
 		goto out;