gnb,rrc: make it possible to use default configs when SRB configs are not present.

srsgnb/src/stack/rrc/rrc_nr_ue.cc

@@ -1409,14 +1409,25 @@ int rrc_nr::ue::update_rlc_bearers(const asn1::rrc_nr::cell_group_cfg_s& cell_gr
   // Add/Mod RLC radio bearers
   for (const rlc_bearer_cfg_s& rb : cell_group_diff.rlc_bearer_to_add_mod_list) {
     srsran::rlc_config_t rlc_cfg;
-    uint8_t rb_id = rb.served_radio_bearer.type().value == rlc_bearer_cfg_s::served_radio_bearer_c_::types_opts::drb_id
-                        ? rb.served_radio_bearer.drb_id()
-                        : rb.served_radio_bearer.srb_id();
+    uint8_t              rb_id = 0;
+    if (rb.served_radio_bearer.type().value == rlc_bearer_cfg_s::served_radio_bearer_c_::types_opts::srb_id) {
+      rb_id = rb.served_radio_bearer.srb_id();
+      if (not rb.rlc_cfg_present) {
+        rlc_cfg = srsran::rlc_config_t::default_rlc_am_nr_config();
+      }
+    } else {
+      rb_id = rb.served_radio_bearer.drb_id();
+      if (not rb.rlc_cfg_present) {
+        logger.error("No RLC config for DRB");
+        // TODO: HANDLE
+        return SRSRAN_ERROR;
+      }
       if (srsran::make_rlc_config_t(rb.rlc_cfg, rb_id, &rlc_cfg) != SRSRAN_SUCCESS) {
         logger.error("Failed to build RLC config");
         // TODO: HANDLE
         return SRSRAN_ERROR;
       }
+    }
     parent->rlc->add_bearer(rnti, rb.lc_ch_id, rlc_cfg);
   }
 

srsue/src/stack/rrc_nr/rrc_nr.cc

@@ -1061,6 +1061,9 @@ bool rrc_nr::apply_rlc_add_mod(const rlc_bearer_cfg_s& rlc_bearer_cfg)
       logger.error("Failed to build RLC config");
       return false;
     }
+  } else if (not is_drb) {
+    logger.error("Using default RLC configs for SRB%d", srb_id);
+    rlc_cfg = rlc_config_t::default_rlc_am_nr_config();
   } else {
     logger.error("In RLC bearer cfg does not contain rlc cfg");
     return false;