fixeria has uploaded this change for review.

View Change

s1ap_proxy: correct handling of UE CONTEXT RELEASE REQUEST

By sending a UE CONTEXT RELEASE REQUEST, the eNB is requesting the
MME to terminate the UE context.  This procedure itself does not
terminate the UE context nor the associated E-RABs.  Therefore, the
S1GW should not terminate E-RAB FSMs upon receiving this PDU.

Keep the function clause in s1ap_proxy, so that the respective
?S1GW_CTR_S1AP_PROXY_IN_PKT_RELEASE_CTX_REQ is properly updated.
Correct the unit test: E-RAB is now expected to remain alive.

Change-Id: If467162e871b7989f0578be30c04d1c32c263c99
Related: osmo-ttcn3-hacks.git Ibbb6da1f2888995608b980e7479758000e94864e
Related: SYS#7738, SYS#7599
---
M src/s1ap_proxy.erl
M test/s1ap_proxy_test.erl
2 files changed, 5 insertions(+), 11 deletions(-)

git pull ssh://gerrit.osmocom.org:29418/erlang/osmo-s1gw refs/changes/90/41490/1

diff --git a/src/s1ap_proxy.erl b/src/s1ap_proxy.erl
index bcba952..502480e 100644
--- a/src/s1ap_proxy.erl
+++ b/src/s1ap_proxy.erl
@@ -604,18 +604,10 @@
 
 %% 9.1.4.5 UE CONTEXT RELEASE REQUEST
 handle_pdu({initiatingMessage,
-            #'InitiatingMessage'{procedureCode = ?'id-UEContextReleaseRequest',
-                                 value = #'UEContextReleaseRequest'{protocolIEs = IEs}}},
-           #proxy_state{erabs = ERABs} = S) ->
+            #'InitiatingMessage'{procedureCode = ?'id-UEContextReleaseRequest'}},
+           #proxy_state{} = S) ->
     ?LOG_DEBUG("Processing UE CONTEXT RELEASE REQUEST"),
     ctr_inc(?S1GW_CTR_S1AP_PROXY_IN_PKT_RELEASE_CTX_REQ, S),
-    %% fetch MME-UE-S1AP-ID value (mandatory IE)
-    #'ProtocolIE-Field'{id = ?'id-MME-UE-S1AP-ID',
-                        value = MMEUEId} = lists:nth(1, IEs),
-    %% poke E-RAB FSMs with the matching MME-UE-S1AP-ID
-    erab_for_each(MMEUEId,
-                  fun erab_fsm:erab_release_ind/1,
-                  dict:to_list(ERABs)),
     {forward, S}; %% forward as-is, there's nothing to patch
 
 %% 9.1.4.6 UE CONTEXT RELEASE COMMAND
diff --git a/test/s1ap_proxy_test.erl b/test/s1ap_proxy_test.erl
index 0cfc645..7a93d1d 100644
--- a/test/s1ap_proxy_test.erl
+++ b/test/s1ap_proxy_test.erl
@@ -462,7 +462,9 @@
      ?_assertMetric(?S1GW_CTR_S1AP_PROXY_OUT_PKT_FWD_ALL, 2 + 1),
      ?_assertMetric(?S1GW_CTR_S1AP_PROXY_OUT_PKT_FWD_PROC, 2),
      ?_assertMetric(?S1GW_CTR_S1AP_PROXY_OUT_PKT_FWD_UNMODIFIED, 1),
-     ?_assertMatch([], s1ap_proxy:fetch_erab_list(Pid))].
+     %% The E-RAB FSM is expected to remain alive and unchanged,
+     %% since this procedure itself does not terminate the UE contect.
+     ?_assertMatch([_], s1ap_proxy:fetch_erab_list(Pid))].
 
 
 test_ue_ctx_release_cmd(#{handler := Pid}) ->

To view, visit change 41490. To unsubscribe, or for help writing mail filters, visit settings.