From: Konstantin Khorenko <redacted>
Date: Fri,  3 Aug 2018 19:21:01 +0300

+struct sctp_stream_out *sctp_stream_out(const struct sctp_stream *stream,
+					__u16 sid)
+{
+	return ((struct sctp_stream_out *)(stream->out)) + sid;
+}
+
+struct sctp_stream_in *sctp_stream_in(const struct sctp_stream *stream,
+				      __u16 sid)
+{
+	return ((struct sctp_stream_in *)(stream->in)) + sid;
+}

I agree with David that these should be in a header file, and marked
inline.