[M] Change in ...osmo-s1gw[master]: s1ap_proxy: handle E-RAB MODIFICATION IND/CNF - gerrit-log

17 Feb 2025

fixeria has submitted this change. ( https://gerrit.osmocom.org/c/erlang/osmo-s1gw/+/39118?usp=email )
Change subject: s1ap_proxy: handle E-RAB MODIFICATION IND/CNF
......................................................................
s1ap_proxy: handle E-RAB MODIFICATION IND/CNF
Change-Id: Icc16a57d40b68bd17c5d207b643927d58176e088
Related: osmo-ttcn3-hacks.git Iec95ca0ecf37290bddfbefce1861f8ae66bf4db1
Related: SYS#7308
---
M include/s1gw_metrics.hrl
M src/s1ap_proxy.erl
M src/s1gw_metrics.erl
M test/erab_fsm_test.erl
M test/s1ap_proxy_test.erl
5 files changed, 209 insertions(+), 19 deletions(-)
Approvals:
  Jenkins Builder: Verified
  pespin: Looks good to me, approved
  laforge: Looks good to me, but someone else must approve

diff --git a/include/s1gw_metrics.hrl b/include/s1gw_metrics.hrl
index a2a0afd..940529b 100644
--- a/include/s1gw_metrics.hrl
+++ b/include/s1gw_metrics.hrl
@@ -24,6 +24,7 @@
 -define(S1GW_CTR_S1AP_PROXY_IN_PKT_ERAB_RELEASE_RSP, [ctr, s1ap, proxy, in_pkt, erab_release_rsp]).
 -define(S1GW_CTR_S1AP_PROXY_IN_PKT_ERAB_RELEASE_IND, [ctr, s1ap, proxy, in_pkt, erab_release_ind]).
 -define(S1GW_CTR_S1AP_PROXY_IN_PKT_ERAB_MOD_IND, [ctr, s1ap, proxy, in_pkt, erab_mod_ind]).
+-define(S1GW_CTR_S1AP_PROXY_IN_PKT_ERAB_MOD_CNF, [ctr, s1ap, proxy, in_pkt, erab_mod_cnf]).
 -define(S1GW_CTR_S1AP_PROXY_IN_PKT_INIT_CTX_REQ, [ctr, s1ap, proxy, in_pkt, init_ctx_req]).
 -define(S1GW_CTR_S1AP_PROXY_IN_PKT_INIT_CTX_RSP, [ctr, s1ap, proxy, in_pkt, init_ctx_rsp]).
 -define(S1GW_CTR_S1AP_PROXY_IN_PKT_RELEASE_CTX_REQ, [ctr, s1ap, proxy, in_pkt, release_ctx_req]).
diff --git a/src/s1ap_proxy.erl b/src/s1ap_proxy.erl
index 402eaaa..db72dab 100644
--- a/src/s1ap_proxy.erl
+++ b/src/s1ap_proxy.erl
@@ -399,6 +399,25 @@
     PDU = {Outcome, Msg#'InitiatingMessage'{value = C1}},
     {{forward, PDU}, S2};
+%% 9.1.3.9 E-RAB MODIFICATION CONFIRM
+handle_pdu({successfulOutcome,
+            #'SuccessfulOutcome'{procedureCode = ?'id-E-RABModificationIndication',
+                                 value = C0}}, S0) ->
+    ?LOG_DEBUG("Processing E-RAB MODIFICATION CONFIRM"),
+    s1gw_metrics:ctr_inc(?S1GW_CTR_S1AP_PROXY_IN_PKT_ERAB_MOD_CNF),
+    IEs = C0#'E-RABModificationConfirm'.protocolIEs,
+    %% E-RAB Modify List
+    %% TODO: handle {error, Reason}
+    {_, S1} = handle_ies(?'id-E-RABModifyListBearerModConf', IEs, S0),
+    %% E-RAB Failed to Modify List
+    %% TODO: handle {error, Reason}
+    {_, S2} = handle_ies(?'id-E-RABFailedToModifyListBearerModConf', IEs, S1),
+    %% E-RAB To Be Released List
+    %% TODO: handle {error, Reason}
+    {_, S3} = handle_ies(?'id-E-RABToBeReleasedListBearerModConf', IEs, S2),
+    %% there's nothing to patch in this PDU, so we forward it as-is
+    {forward, S3};
+
 %% 9.1.4.1 INITIAL CONTEXT SETUP REQUEST
 handle_pdu({Outcome = initiatingMessage,
             #'InitiatingMessage'{procedureCode = ?'id-InitialContextSetup',
@@ -700,16 +719,31 @@
             {{error, erab_not_registered}, S}
     end;
-%% E-RAB MODIFICATION INDICATION related IEs
+%% 9.1.3.8 E-RAB MODIFICATION INDICATION related IEs
 handle_ie([?'id-E-RABToBeModifiedListBearerModInd'], C, S) ->
     %% This IE contains a list of BearerModInd, so patch inner IEs
     handle_ies(?'id-E-RABToBeModifiedItemBearerModInd', C, S);
handle_ie([?'id-E-RABToBeModifiedItemBearerModInd',
            ?'id-E-RABToBeModifiedListBearerModInd'],
-          #'E-RABToBeModifiedItemBearerModInd'{} = C, S) ->
-    %% TODO: find and poke an E-RAB FSM associated with this E-RAB
-    {{ok, C}, S};
+          #'E-RABToBeModifiedItemBearerModInd'{'e-RAB-ID' = ERABId,
+                                               'transportLayerAddress' = TLA_In,
+                                               'dL-GTP-TEID' = << TEID_In:32/big >>} = C0, S) ->
+    %% poke E-RAB FSM
+    case erab_fsm_find(ERABId, S) of
+        {ok, Pid} ->
+            case erab_fsm:erab_modify_ind(Pid, {TEID_In, TLA_In}) of
+                {ok, {TEID_Out, TLA_Out}} ->
+                    C1 = C0#'E-RABToBeModifiedItemBearerModInd'{'transportLayerAddress' = TLA_Out,
+                                                                'dL-GTP-TEID' = << TEID_Out:32/big >>},
+                    {{ok, C1}, S};
+                {error, Reason} ->
+                    {{error, Reason}, S}
+            end;
+        error ->
+            ?LOG_ERROR("E-RAB-ID ~p is not registered", [erab_uid(ERABId, S)]),
+            {{error, erab_not_registered}, S}
+    end;
handle_ie([?'id-E-RABNotToBeModifiedListBearerModInd'], C, S) ->
     %% This IE contains a list of BearerModInd, so patch inner IEs
@@ -717,9 +751,77 @@
handle_ie([?'id-E-RABNotToBeModifiedItemBearerModInd',
            ?'id-E-RABNotToBeModifiedListBearerModInd'],
-          #'E-RABNotToBeModifiedItemBearerModInd'{} = C, S) ->
-    %% TODO: find and poke an E-RAB FSM associated with this E-RAB
-    {{ok, C}, S};
+          #'E-RABNotToBeModifiedItemBearerModInd'{'e-RAB-ID' = ERABId} = C0, S) ->
+    %% poke E-RAB FSM
+    case erab_fsm_find(ERABId, S) of
+        {ok, Pid} ->
+            %% Ignore F-TEID in the original message, just replace it with C2U F-TEID
+            Info = erab_fsm:fetch_info(Pid),
+            case proplists:get_value(f_teid_c2u, Info) of
+                {TEID, TLA} ->
+                    C1 = C0#'E-RABNotToBeModifiedItemBearerModInd'{'transportLayerAddress' = TLA,
+                                                                   'dL-GTP-TEID' = << TEID:32/big >>},
+                    {{ok, C1}, S};
+                undefined ->
+                    ?LOG_ERROR("E-RAB-ID ~p :: missing C2U F-TEID", [erab_uid(ERABId, S)]),
+                    {{error, missing_f_teid}, S}
+            end;
+        error ->
+            ?LOG_ERROR("E-RAB-ID ~p is not registered", [erab_uid(ERABId, S)]),
+            {{error, erab_not_registered}, S}
+    end;
+
+%% 9.1.3.9 E-RAB MODIFICATION CONFIRM related IEs
+handle_ie([?'id-E-RABModifyListBearerModConf'], C, S) ->
+    %% This IE contains a list of BearerModConf, so patch inner IEs
+    handle_ies(?'id-E-RABModifyItemBearerModConf', C, S);
+
+handle_ie([?'id-E-RABModifyItemBearerModConf',
+           ?'id-E-RABModifyListBearerModConf'],
+          #'E-RABModifyItemBearerModConf'{'e-RAB-ID' = ERABId} = C, S) ->
+    %% poke E-RAB FSM
+    case erab_fsm_find(ERABId, S) of
+        {ok, Pid} ->
+            ok = erab_fsm:erab_modify_cnf(Pid, ack),
+            {{ok, C}, S};
+        error ->
+            ?LOG_ERROR("E-RAB-ID ~p is not registered", [erab_uid(ERABId, S)]),
+            {{error, erab_not_registered}, S}
+    end;
+
+handle_ie([?'id-E-RABFailedToModifyListBearerModConf'], C, S) ->
+    %% This IE contains a list of E-RABItem, so patch inner IEs
+    handle_ies(?'id-E-RABItem', C, S);
+
+handle_ie([?'id-E-RABItem',
+           ?'id-E-RABFailedToModifyListBearerModConf'],
+          #'E-RABItem'{'e-RAB-ID' = ERABId} = C, S) ->
+    %% poke E-RAB FSM
+    case erab_fsm_find(ERABId, S) of
+        {ok, Pid} ->
+            ok = erab_fsm:erab_modify_cnf(Pid, nack),
+            {{ok, C}, S};
+        error ->
+            ?LOG_ERROR("E-RAB-ID ~p is not registered", [erab_uid(ERABId, S)]),
+            {{error, erab_not_registered}, S}
+    end;
+
+handle_ie([?'id-E-RABToBeReleasedListBearerModConf'], C, S) ->
+    %% This IE contains a list of E-RABItem, so patch inner IEs
+    handle_ies(?'id-E-RABItem', C, S);
+
+handle_ie([?'id-E-RABItem',
+           ?'id-E-RABToBeReleasedListBearerModConf'],
+          #'E-RABItem'{'e-RAB-ID' = ERABId} = C, S) ->
+    %% poke E-RAB FSM
+    case erab_fsm_find(ERABId, S) of
+        {ok, Pid} ->
+            ok = erab_fsm:erab_release_ind(Pid),
+            {{ok, C}, S};
+        error ->
+            ?LOG_ERROR("E-RAB-ID ~p is not registered", [erab_uid(ERABId, S)]),
+            {{error, erab_not_registered}, S}
+    end;
%% INITIAL CONTEXT SETUP REQUEST related IEs
 handle_ie([?'id-E-RABToBeSetupListCtxtSUReq'], C, S) ->
diff --git a/src/s1gw_metrics.erl b/src/s1gw_metrics.erl
index c2785de..9f7b2e8 100644
--- a/src/s1gw_metrics.erl
+++ b/src/s1gw_metrics.erl
@@ -75,6 +75,7 @@
     ?S1GW_CTR_S1AP_PROXY_IN_PKT_ERAB_RELEASE_RSP,           %% E-RAB RELEASE.rsp PDUs
     ?S1GW_CTR_S1AP_PROXY_IN_PKT_ERAB_RELEASE_IND,           %% E-RAB RELEASE.ind PDUs
     ?S1GW_CTR_S1AP_PROXY_IN_PKT_ERAB_MOD_IND,               %% E-RAB MODIFY.ind PDUs
+    ?S1GW_CTR_S1AP_PROXY_IN_PKT_ERAB_MOD_CNF,               %% E-RAB MODIFY.cnf PDUs
     ?S1GW_CTR_S1AP_PROXY_IN_PKT_INIT_CTX_REQ,               %% INITIAL CONTEXT SETUP.req PDUs
     ?S1GW_CTR_S1AP_PROXY_IN_PKT_INIT_CTX_RSP,               %% INITIAL CONTEXT SETUP.rsp PDUs
     ?S1GW_CTR_S1AP_PROXY_IN_PKT_RELEASE_CTX_REQ,            %% UE CONTEXT RELEASE.req PDUs
diff --git a/test/erab_fsm_test.erl b/test/erab_fsm_test.erl
index 3740f9a..a3dfb4d 100644
--- a/test/erab_fsm_test.erl
+++ b/test/erab_fsm_test.erl
@@ -51,6 +51,9 @@
       ?TC(fun test_erab_setup_pfcp_modify_error/1)}].
+%% 8.2.4.2 Interactions with E-RAB Setup procedure or E-RAB Modify procedure:
+%% TODO: test E-RAB MODIFY IND/CNF during E-RAB SETUP
+%% TODO: test E-RAB MODIFY IND/CNF during E-RAB MODIFY
 erab_modify_test_() ->
     [{"E-RAB MODIFY REQ :: ACK",
       ?TC(fun test_erab_modify_req_ack/1)},
diff --git a/test/s1ap_proxy_test.erl b/test/s1ap_proxy_test.erl
index 6c04d1b..74f3f05 100644
--- a/test/s1ap_proxy_test.erl
+++ b/test/s1ap_proxy_test.erl
@@ -46,8 +46,12 @@
       ?TC(fun test_e_rab_modify_req_rsp/1)},
      {"E-RAB MODIFY REQUEST/RESPONSE (failure)",
       ?TC(fun test_e_rab_modify_req_rsp_fail/1)},
-     {"E-RAB MODIFICATION INDICATION",
-      ?TC(fun test_e_rab_modify_ind/1)},
+     {"E-RAB MODIFICATION INDICATION (modified)",
+      ?TC(fun test_e_rab_modify_ind_cnf_modified/1)},
+     {"E-RAB MODIFICATION INDICATION (not modified)",
+      ?TC(fun test_e_rab_modify_ind_cnf_not_modified/1)},
+     {"E-RAB MODIFICATION INDICATION (release)",
+      ?TC(fun test_e_rab_modify_ind_cnf_release/1)},
      {"INITIAL CONTEXT SETUP REQUEST/RESPONSE",
       ?TC(fun test_initial_context_setup/1)},
      {"UE CONTEXT RELEASE REQUEST",
@@ -168,13 +172,70 @@
      ?_assertEqual([], s1ap_proxy:fetch_erab_list(Pid))].
-test_e_rab_modify_ind(#{handler := Pid}) ->
-    %% [eNB -> MME] E-RAB MODIFICATION INDICATION
-    ModifyIndIn = e_rab_modify_ind_pdu(?ADDR_U2A, ?TEID_U2A),
-    %% XXX: not implemented, we should actually expect ?ADDR_C2U, ?TEID_C2U
-    ModifyIndExp = e_rab_modify_ind_pdu(?ADDR_U2A, ?TEID_U2A),
+test_e_rab_modify_ind_cnf_modified(#{handler := Pid}) ->
+    %% [eNB <- MME] E-RAB SETUP REQUEST
+    SetupReq = e_rab_setup_req_pdu(?ADDR_U2C, ?TEID_U2C),
+    %% [eNB -> MME] E-RAB SETUP RESPONSE
+    SetupRsp = e_rab_setup_rsp_pdu(?ADDR_U2A, ?TEID_U2A),
+    %% [eNB -> S1GW] -> MME E-RAB MODIFICATION INDICATION (new F-TEID)
+    ModifyIndIn = e_rab_modify_ind_pdu(?ADDR_U2AM, ?TEID_U2AM),
+    %% eNB -> [S1GW -> MME] E-RAB MODIFICATION INDICATION
+    %% for the MME F-TEID remains unchanged
+    ModifyIndExp = e_rab_modify_ind_pdu(?ADDR_C2U, ?TEID_C2U),
+    %% [eNB <- MME] E-RAB MODIFICATION CONFIRMATION
+    ModifyCnf = e_rab_modify_cnf_pdu(modified),
+    %% [eNB -> MME] E-RAB RELEASE INDICATION
+    ReleaseInd = e_rab_release_ind_pdu(),
-    [?_assertEqual({forward, ModifyIndExp}, s1ap_proxy:process_pdu(Pid, ModifyIndIn))].
+    [?_assertMatch({forward, _}, s1ap_proxy:process_pdu(Pid, SetupReq)),
+     ?_assertMatch({forward, _}, s1ap_proxy:process_pdu(Pid, SetupRsp)),
+     ?_assertEqual({forward, ModifyIndExp}, s1ap_proxy:process_pdu(Pid, ModifyIndIn)),
+     ?_assertEqual({forward, ModifyCnf}, s1ap_proxy:process_pdu(Pid, ModifyCnf)),
+     ?_assertEqual({forward, ReleaseInd}, s1ap_proxy:process_pdu(Pid, ReleaseInd)),
+     ?_assertEqual([], s1ap_proxy:fetch_erab_list(Pid))].
+
+
+test_e_rab_modify_ind_cnf_not_modified(#{handler := Pid}) ->
+    %% [eNB <- MME] E-RAB SETUP REQUEST
+    SetupReq = e_rab_setup_req_pdu(?ADDR_U2C, ?TEID_U2C),
+    %% [eNB -> MME] E-RAB SETUP RESPONSE
+    SetupRsp = e_rab_setup_rsp_pdu(?ADDR_U2A, ?TEID_U2A),
+    %% [eNB -> S1GW] -> MME E-RAB MODIFICATION INDICATION (new F-TEID)
+    ModifyIndIn = e_rab_modify_ind_pdu(?ADDR_U2AM, ?TEID_U2AM),
+    %% eNB -> [S1GW -> MME] E-RAB MODIFICATION INDICATION
+    %% for the MME F-TEID remains unchanged
+    ModifyIndExp = e_rab_modify_ind_pdu(?ADDR_C2U, ?TEID_C2U),
+    %% [eNB <- MME] E-RAB MODIFICATION CONFIRMATION
+    ModifyCnf = e_rab_modify_cnf_pdu(not_modified),
+    %% [eNB -> MME] E-RAB RELEASE INDICATION
+    ReleaseInd = e_rab_release_ind_pdu(),
+
+    [?_assertMatch({forward, _}, s1ap_proxy:process_pdu(Pid, SetupReq)),
+     ?_assertMatch({forward, _}, s1ap_proxy:process_pdu(Pid, SetupRsp)),
+     ?_assertEqual({forward, ModifyIndExp}, s1ap_proxy:process_pdu(Pid, ModifyIndIn)),
+     ?_assertEqual({forward, ModifyCnf}, s1ap_proxy:process_pdu(Pid, ModifyCnf)),
+     ?_assertEqual({forward, ReleaseInd}, s1ap_proxy:process_pdu(Pid, ReleaseInd)),
+     ?_assertEqual([], s1ap_proxy:fetch_erab_list(Pid))].
+
+
+test_e_rab_modify_ind_cnf_release(#{handler := Pid}) ->
+    %% [eNB <- MME] E-RAB SETUP REQUEST
+    SetupReq = e_rab_setup_req_pdu(?ADDR_U2C, ?TEID_U2C),
+    %% [eNB -> MME] E-RAB SETUP RESPONSE
+    SetupRsp = e_rab_setup_rsp_pdu(?ADDR_U2A, ?TEID_U2A),
+    %% [eNB -> S1GW] -> MME E-RAB MODIFICATION INDICATION (new F-TEID)
+    ModifyIndIn = e_rab_modify_ind_pdu(?ADDR_U2AM, ?TEID_U2AM),
+    %% eNB -> [S1GW -> MME] E-RAB MODIFICATION INDICATION
+    %% for the MME F-TEID remains unchanged
+    ModifyIndExp = e_rab_modify_ind_pdu(?ADDR_C2U, ?TEID_C2U),
+    %% [eNB <- MME] E-RAB MODIFICATION CONFIRMATION
+    ModifyCnf = e_rab_modify_cnf_pdu(release),
+
+    [?_assertMatch({forward, _}, s1ap_proxy:process_pdu(Pid, SetupReq)),
+     ?_assertMatch({forward, _}, s1ap_proxy:process_pdu(Pid, SetupRsp)),
+     ?_assertEqual({forward, ModifyIndExp}, s1ap_proxy:process_pdu(Pid, ModifyIndIn)),
+     ?_assertEqual({forward, ModifyCnf}, s1ap_proxy:process_pdu(Pid, ModifyCnf)),
+     ?_assertEqual([], s1ap_proxy:fetch_erab_list(Pid))].
test_initial_context_setup(#{handler := Pid}) ->
@@ -349,15 +410,37 @@
 %% [eNB -> MME] E-RAB MODIFICATION INDICATION
 e_rab_modify_ind_pdu(TLA, TEID) when is_binary(TLA),
                                      is_integer(TEID) ->
-    << 16#00, 16#32, 16#00, 16#24, 16#00, 16#00, 16#03, 16#00,
-       16#00, 16#00, 16#02, 16#00, 16#02, 16#00, 16#08, 16#00,
-       16#04, 16#80, 16#06, 16#69, 16#2d, 16#00, 16#c7, 16#00,
-       16#0f, 16#00, 16#00, 16#c8, 16#00, 16#0a, 16#0a, 16#1f,
+    << 16#00, 16#32, 16#00, 16#22, 16#00, 16#00, 16#03, 16#00,
+       16#00, 16#00, 16#02, 16#00, 16#07, 16#00, 16#08, 16#00,
+       16#02, 16#00, 16#09, 16#00, 16#c7, 16#00, 16#0f, 16#00,
+       16#00, 16#c8, 16#00, 16#0a, 16#0c, 16#1f,
        TLA/bytes, %% transportLayerAddress (IPv4)
        TEID:32/big %% GTP-TEID
     >>.
+%% [eNB -> MME] E-RAB MODIFICATION CONFIRMATION
+e_rab_modify_cnf_pdu(Res) ->
+    IEs = case Res of
+        modified ->
+            << 16#00, 16#cb, 16#40, 16#06, 16#00,
+               16#00, 16#cc, 16#40, 16#01, 16#0c >>;
+        not_modified ->
+            %% cause: transport: transport-resource-unavailable (0)
+            << 16#00, 16#cd, 16#40, 16#07, 16#00,
+               16#00, 16#23, 16#40, 16#02, 16#0c, 16#20 >>;
+        release ->
+            %% cause: transport: transport-resource-unavailable (0)
+            << 16#00, 16#d2, 16#40, 16#07, 16#00,
+               16#00, 16#23, 16#40, 16#02, 16#0c, 16#20 >>
+    end,
+    << 16#20, 16#32, 16#00, (15 + byte_size(IEs)),
+       16#00, 16#00, 16#03, 16#00, 16#00, 16#40, 16#02, 16#00,
+       16#07, 16#00, 16#08, 16#40, 16#02, 16#00, 16#09,
+       IEs/bytes
+    >>.
+
+
 %% [eNB <- MME] INITIAL CONTEXT SETUP REQUEST
 initial_context_setup_req_pdu(TLA, TEID) when is_binary(TLA),
                                               is_integer(TEID) ->
-- 
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Gerrit-MessageType: merged
Gerrit-Project: erlang/osmo-s1gw
Gerrit-Branch: master
Gerrit-Change-Id: Icc16a57d40b68bd17c5d207b643927d58176e088
Gerrit-Change-Number: 39118
Gerrit-PatchSet: 7
Gerrit-Owner: fixeria vyanitskiy@sysmocom.de
Gerrit-Reviewer: Jenkins Builder
Gerrit-Reviewer: fixeria vyanitskiy@sysmocom.de
Gerrit-Reviewer: laforge laforge@osmocom.org
Gerrit-Reviewer: pespin pespin@sysmocom.de



    