diff --git a/src/sctp_common/common.h b/src/sctp_common/common.h
new file mode 100644
index 0000000..cf441f7
--- /dev/null
+++ b/src/sctp_common/common.h
@@ -0,0 +1,24 @@
+#pragma once
+#include <rawrtcc/code.h>
+#include <rawrtcdc/external.h>
+#include <re.h>
+
+enum rawrtc_code rawrtc_sctp_common_dtls_role_getter(
+    enum rawrtc_external_dtls_role* const rolep,  // de-referenced, not checked
+    void* const arg  // not checked
+);
+
+enum rawrtc_code rawrtc_sctp_common_dtls_transport_state_getter(
+    enum rawrtc_external_dtls_transport_state* const statep,  // de-referenced, not checked
+    void* const arg  // not checked
+);
+
+enum rawrtc_code rawrtc_sctp_common_sctp_transport_outbound_handler(
+    struct mbuf* const buffer,  // not checked
+    uint8_t const tos,
+    uint8_t const set_df,
+    void* const arg  // not checked
+);
+
+void rawrtc_sctp_common_sctp_transport_detach_handler(void* const arg  // not checked
+);