Configure Short PDCP NR SN support

srsue/hdr/stack/rrc/rrc_nr.h

@@ -41,6 +41,7 @@ struct core_less_args_t {
 struct rrc_nr_args_t {
   core_less_args_t      coreless;
   uint32_t              sim_nr_meas_pci;
+  bool                  pdcp_short_sn_support;
   std::string           supported_bands_nr_str;
   std::vector<uint32_t> supported_bands_nr;
   std::vector<uint32_t> supported_bands_eutra;

srsue/src/main.cc

@@ -130,6 +130,7 @@ static int parse_args(all_args_t* args, int argc, char* argv[])
     ("rrc.mbms_service_id",     bpo::value<int32_t>(&args->stack.rrc.mbms_service_id)->default_value(-1),                         "MBMS service id for autostart (-1 means disabled)")
     ("rrc.mbms_service_port",   bpo::value<uint32_t>(&args->stack.rrc.mbms_service_port)->default_value(4321),                    "Port of the MBMS service")
     ("rrc.nr_measurement_pci",  bpo::value<uint32_t>(&args->stack.rrc_nr.sim_nr_meas_pci)->default_value(500),                    "NR PCI for the simulated NR measurement")
+    ("rrc.nr_short_sn_support", bpo::value<bool>(&args->stack.rrc_nr.pdcp_short_sn_support)->default_value(true),                 "Announce PDCP short SN support")
 
     ("nas.apn",               bpo::value<string>(&args->stack.nas.apn_name)->default_value(""),          "Set Access Point Name (APN) for data services")
     ("nas.apn_protocol",      bpo::value<string>(&args->stack.nas.apn_protocol)->default_value(""),  "Set Access Point Name (APN) protocol for data services")

srsue/src/stack/rrc/rrc_nr.cc

@@ -379,7 +379,7 @@ void rrc_nr::get_nr_capabilities(srsran::byte_buffer_t* nr_caps_pdu)
   nr_cap.rlc_params_present                  = true;
   nr_cap.rlc_params.um_with_short_sn_present = true;
   nr_cap.rlc_params.um_with_long_sn_present  = true;
-  nr_cap.pdcp_params.short_sn_present        = true;
+  nr_cap.pdcp_params.short_sn_present        = args.pdcp_short_sn_support;
 
   // Pack nr_caps
   asn1::bit_ref bref(nr_caps_pdu->msg, nr_caps_pdu->get_tailroom());

srsue/ue.conf.example

@@ -155,6 +155,7 @@ imei = 353490069873319
 #                       (default -1 means disabled)
 # mbms_service_port:    Port of the MBMS service
 # nr_measurement_pci:   NR PCI for the simulated NR measurement. Default: 500
+# nr_short_sn_support:  Announce PDCP short SN support. Default: true
 #####################################################################
 [rrc]
 #ue_category       = 4