Wrong handling of error when PFCP Session Establishment fails
When the PFCP Session Establishment towards VPP-UPF fails, it adds custom IEs. It seems these are not understood by the PFCP layer, resulting in an exception. This exception is handled in smf_app(), but the answer should be handled in procedure so we can send an error towards AMF (PDU session establishment reject). At the moment, the SMF just does not reply to the AMF.
The trace is from the feature_upf_selection branch where the SMF sends the wrong IEs. Still, we should support this scenario.
It is also reproducible when the PFCP Association between SMF and UPF has failed before (e.g. temporary network issue)
[2022-07-21T08:24:41.884541] [smf] [smf_app] [info ] Sending ITTI message 37itti_n4_session_establishment_request to task TASK_SMF_N4
[2022-07-21T08:24:41.884857] [smf] [pfcp ] [trace] Sending PFCP_SESSION_ESTABLISHMENT_REQUEST, seq 1556352 seid 0x0
[2022-07-21T08:24:41.914035] [smf] [smf_n4 ] [info ] handle_receive(181 bytes)
[2022-07-21T08:24:41.914269] [smf] [smf_n4 ] [info ] handle_receive exception PFCP IE TLV 114 Bad Length 5 Exception /openair-smf/src/pfcp/3gpp_29.244.hpp:6595
smf_issue_no_response_to_failed_session_establishment.pcapng
Edited by Stefan Spettel