Merge remote-tracking branch 'origin/gtp-unit-test' into integration_2026_w08 (!3918)

Add a simple GTP unit test

Add a simple unit test for GTP that as of now tests the main
functionality, i.e., for a single UE, set up a bearer between two
endpoints and checking that traffic sending works. This is a start to
extend it further, e.g., with API changes, extensions to support new
functionality such as IPv6, and refactorings.

A number of supporting cleanup has been done as well.

CMakeLists.txt

@@ -648,7 +648,6 @@ include_directories("${OPENAIR3_DIR}/S1AP")
 include_directories("${OPENAIR2_DIR}/X2AP")
 include_directories("${OPENAIR2_DIR}/M2AP")
 include_directories("${OPENAIR2_DIR}/F1AP")
-include_directories("${OPENAIR3_DIR}/ocp-gtpu")
 include_directories("${OPENAIR3_DIR}/M3AP")
 include_directories("${OPENAIR3_DIR}/MME_APP")
 include_directories("${OPENAIR_DIR}/radio/COMMON")
@@ -1149,7 +1148,7 @@ set(L2_SRC
   ${RRC_DIR}/rrc_eNB_S1AP.c
   ${RRC_DIR}/rrc_eNB_M2AP.c
   ${RRC_DIR}/rrc_eNB_UE_context.c
-  ${NR_RRC_DIR}/rrc_gNB_UE_context.c
+  ${RRC_DIR}/rrc_eNB_GTPV1U.c
   ${RRC_DIR}/rrc_common.c
   ${RRC_DIR}/L2_interface.c
   ${RRC_DIR}/L2_interface_common.c
@@ -1396,15 +1395,6 @@ include_directories("${OPENAIR1_DIR}/SCHED_NR_UE")
 # CN libs
 ##########################
 
-add_library (GTPV1U
-  ${RRC_DIR}/rrc_eNB_GTPV1U.c
-  ${OPENAIR3_DIR}/ocp-gtpu/gtp_itf.cpp
-  ${OPENAIR3_DIR}/ocp-gtpu/gtpu_extensions.c
-  )
-target_link_libraries(GTPV1U PRIVATE asn1_nr_rrc_hdrs asn1_lte_rrc_hdrs)
-target_link_libraries(GTPV1U PRIVATE SIMU ds)
-include_directories(${OPENAIR3_DIR}/ocp-gtp)
-
 set (MME_APP_SRC
   ${OPENAIR3_DIR}/MME_APP/mme_app.c
   ${OPENAIR3_DIR}/MME_APP/mme_config.c