ngap,sctp: define NGAP port in common location

Author: robertfalkenberg

include/srsran/gateways/sctp_network_gateway.h

@@ -23,6 +23,7 @@ constexpr uint16_t E2_CP_PPID = 70; ///< E2-CP PPID assigned by IANA
 constexpr uint16_t E2_UP_PPID = 71; ///< E2-UP PPID assigned by IANA
 constexpr uint16_t E2_DU_PPID = 72; ///< E2-DU PPID assigned by IANA
 
+constexpr uint16_t NGAP_PORT = 38412; ///< NGAP port, see TS 38.412, section 7.
 constexpr uint16_t F1AP_PORT = 38472; ///< F1AP port, see TS 38.472, section 7.
 
 /// \brief Configuration for SCTP network gateway that is common to the server and client.

include/srsran/ngap/gateways/n2_connection_client_factory.h

@@ -32,7 +32,7 @@ struct n2_connection_client_config {
     std::string            bind_address;
     std::string            bind_interface;
     std::string            amf_address;
-    int                    amf_port = 38412;
+    int                    amf_port = NGAP_PORT;
     std::optional<int32_t> rto_initial;
     std::optional<int32_t> rto_min;
     std::optional<int32_t> rto_max;
@@ -52,4 +52,4 @@ struct n2_connection_client_config {
 std::unique_ptr<n2_connection_client> create_n2_connection_client(const n2_connection_client_config& params);
 
 } // namespace srs_cu_cp
-} // namespace srsran
+} // namespace srsran