[M] Change in ...osmo-s1gw[master]: s1ap_proxy: implement patching of INITIAL CONTEXT SETUP REQ/RSP - gerrit-log

6 Jun 2024

laforge has submitted this change. ( https://gerrit.osmocom.org/c/erlang/osmo-s1gw/+/37104?usp=email )
Change subject: s1ap_proxy: implement patching of INITIAL CONTEXT SETUP REQ/RSP
......................................................................
s1ap_proxy: implement patching of INITIAL CONTEXT SETUP REQ/RSP
Change-Id: Ia0d8f8d81756bcce5f518caee8887cf5822aaa08
---
M src/s1ap_proxy.erl
M test/s1ap_proxy_test.erl
2 files changed, 132 insertions(+), 0 deletions(-)
Approvals:
  Jenkins Builder: Verified
  laforge: Looks good to me, approved
  osmith: Looks good to me, but someone else must approve

diff --git a/src/s1ap_proxy.erl b/src/s1ap_proxy.erl
index 0c6cba0..82e4039 100644
--- a/src/s1ap_proxy.erl
+++ b/src/s1ap_proxy.erl
@@ -124,6 +124,26 @@
     NewContent = Content#'E-RABModificationIndication'{protocolIEs = IEs2},
     handle_pdu_new(Data, {Outcome, Pdu#'InitiatingMessage'{value = NewContent}});
+%% 9.1.4.1 INITIAL CONTEXT SETUP REQUEST
+handle_pdu(Data, {Outcome = initiatingMessage,
+                  #'InitiatingMessage'{procedureCode = ?'id-InitialContextSetup',
+                                       value = Content} = Pdu}) ->
+    logger:debug("Patching INITIAL CONTEXT SETUP REQUEST"),
+    IEs = handle_ies(Content#'InitialContextSetupRequest'.protocolIEs,
+                     ?'id-E-RABToBeSetupListCtxtSUReq'),
+    NewContent = Content#'InitialContextSetupRequest'{protocolIEs = IEs},
+    handle_pdu_new(Data, {Outcome, Pdu#'InitiatingMessage'{value = NewContent}});
+
+%% 9.1.4.3 INITIAL CONTEXT SETUP RESPONSE
+handle_pdu(Data, {Outcome = successfulOutcome,
+                  #'SuccessfulOutcome'{procedureCode = ?'id-InitialContextSetup',
+                                       value = Content} = Pdu}) ->
+    logger:debug("Patching INITIAL CONTEXT SETUP RESPONSE"),
+    IEs = handle_ies(Content#'InitialContextSetupResponse'.protocolIEs,
+                     ?'id-E-RABSetupListCtxtSURes'),
+    NewContent = Content#'InitialContextSetupResponse'{protocolIEs = IEs},
+    handle_pdu_new(Data, {Outcome, Pdu#'SuccessfulOutcome'{value = NewContent}});
+
 %% Proxy all other messages unmodified
 handle_pdu(Data, _Pdu) ->
     Data.
@@ -179,6 +199,30 @@
     TLA = transp_layer_addr(mme_loc_addr),
     Content#'E-RABNotToBeModifiedItemBearerModInd'{transportLayerAddress = TLA};
+%% INITIAL CONTEXT SETUP REQUEST related IEs
+handle_ie(#'ProtocolIE-Field'{id = ?'id-E-RABToBeSetupListCtxtSUReq',
+                              value = Content}) ->
+    %% This IE contains a list of CtxtSUReq, so patch inner IEs
+    handle_ies(Content, ?'id-E-RABToBeSetupItemCtxtSUReq');
+
+handle_ie(#'ProtocolIE-Field'{id = ?'id-E-RABToBeSetupItemCtxtSUReq',
+                              value = Content}) ->
+    %% eNB -> MME direction: we pass our MME facing local address
+    TLA = transp_layer_addr(mme_loc_addr),
+    Content#'E-RABToBeSetupItemCtxtSUReq'{transportLayerAddress = TLA};
+
+%% INITIAL CONTEXT SETUP RESPONSE related IEs
+handle_ie(#'ProtocolIE-Field'{id = ?'id-E-RABSetupListCtxtSURes',
+                              value = Content}) ->
+    %% This IE contains a list of CtxtSURes, so patch inner IEs
+    handle_ies(Content, ?'id-E-RABSetupItemCtxtSURes');
+
+handle_ie(#'ProtocolIE-Field'{id = ?'id-E-RABSetupItemCtxtSURes',
+                              value = Content}) ->
+    %% MME -> eNB direction: we pass our eNB facing local address
+    TLA = transp_layer_addr(s1gw_bind_addr),
+    Content#'E-RABSetupItemCtxtSURes'{transportLayerAddress = TLA};
+
 %% Catch-all variant, which should not be called normally
 handle_ie(#'ProtocolIE-Field'{value = Content} = IE) ->
     logger:error("[BUG] Unhandled S1AP IE: ~p", [IE]),
diff --git a/test/s1ap_proxy_test.erl b/test/s1ap_proxy_test.erl
index 4123085..e694197 100644
--- a/test/s1ap_proxy_test.erl
+++ b/test/s1ap_proxy_test.erl
@@ -110,4 +110,83 @@
     application:set_env(osmo_s1gw, mme_loc_addr, ?EXP_ADDR_STR),
     ?assertEqual(ExpData, s1ap_proxy:handle_pdu(OrigData)).
+
+%% [eNB -> MME] INITIAL CONTEXT SETUP REQUEST
+initial_context_setup_req_pdu(TLA, TEID) when is_binary(TLA),
+                                              is_binary(TEID) ->
+    << 16#00, 16#09, 16#00, 16#81, 16#10, 16#00, 16#00, 16#07,
+       16#00, 16#00, 16#00, 16#02, 16#00, 16#01, 16#00, 16#08,
+       16#00, 16#02, 16#00, 16#01, 16#00, 16#42, 16#00, 16#0a,
+       16#18, 16#3b, 16#9a, 16#ca, 16#00, 16#60, 16#3b, 16#9a,
+       16#ca, 16#00, 16#00, 16#18, 16#00, 16#80, 16#b5, 16#00,
+       16#00, 16#34, 16#00, 16#80, 16#af, 16#45, 16#00, 16#09,
+       16#20, 16#0f, 16#80,
+       TLA/bytes, %% transportLayerAddress (IPv4)
+       TEID/bytes, %% GTP-TEID
+       16#80, 16#9f, 16#27, 16#bd, 16#de,
+       16#61, 16#4e, 16#02, 16#07, 16#42, 16#02, 16#29, 16#06,
+       16#40, 16#32, 16#f8, 16#10, 16#00, 16#01, 16#00, 16#6e,
+       16#52, 16#05, 16#c1, 16#01, 16#09, 16#09, 16#08, 16#69,
+       16#6e, 16#74, 16#65, 16#72, 16#6e, 16#65, 16#74, 16#05,
+       16#01, 16#c0, 16#a8, 16#64, 16#02, 16#5e, 16#06, 16#fe,
+       16#fe, 16#fa, 16#fa, 16#02, 16#02, 16#58, 16#32, 16#27,
+       16#4d, 16#80, 16#80, 16#21, 16#10, 16#02, 16#00, 16#00,
+       16#10, 16#81, 16#06, 16#08, 16#08, 16#08, 16#08, 16#83,
+       16#06, 16#08, 16#08, 16#04, 16#04, 16#00, 16#0d, 16#04,
+       16#08, 16#08, 16#08, 16#08, 16#00, 16#0d, 16#04, 16#08,
+       16#08, 16#04, 16#04, 16#00, 16#03, 16#10, 16#20, 16#01,
+       16#48, 16#60, 16#48, 16#60, 16#00, 16#00, 16#00, 16#00,
+       16#00, 16#00, 16#00, 16#00, 16#88, 16#88, 16#00, 16#03,
+       16#10, 16#20, 16#01, 16#48, 16#60, 16#48, 16#60, 16#00,
+       16#00, 16#00, 16#00, 16#00, 16#00, 16#00, 16#00, 16#88,
+       16#44, 16#00, 16#10, 16#02, 16#05, 16#aa, 16#50, 16#0b,
+       16#f6, 16#32, 16#f8, 16#10, 16#00, 16#02, 16#01, 16#c0,
+       16#00, 16#02, 16#86, 16#13, 16#32, 16#f8, 16#10, 16#00,
+       16#01, 16#23, 16#05, 16#f4, 16#04, 16#94, 16#25, 16#f8,
+       16#64, 16#02, 16#01, 16#08, 16#00, 16#6b, 16#00, 16#05,
+       16#1c, 16#00, 16#0e, 16#00, 16#00, 16#00, 16#49, 16#00,
+       16#20, 16#57, 16#5d, 16#d3, 16#66, 16#69, 16#73, 16#4c,
+       16#8c, 16#48, 16#42, 16#76, 16#5f, 16#fe, 16#f9, 16#bd,
+       16#d5, 16#89, 16#08, 16#ae, 16#f6, 16#f4, 16#88, 16#62,
+       16#22, 16#d7, 16#80, 16#fb, 16#36, 16#33, 16#d9, 16#9e,
+       16#9f, 16#00, 16#c0, 16#40, 16#08, 16#35, 16#87, 16#61,
+       16#10, 16#03, 16#ff, 16#ff, 16#74
+    >>.
+
+initial_context_setup_req_test() ->
+    %% Original input data
+    TEID = << 16#00, 16#00, 16#71, 16#23 >>,
+    OrigTLA = << 16#c0, 16#a8, 16#02, 16#d2 >>,
+    OrigData = initial_context_setup_req_pdu(OrigTLA, TEID),
+
+    %% Expected output data
+    ExpData = initial_context_setup_req_pdu(?EXP_ADDR_BIN, TEID),
+
+    application:set_env(osmo_s1gw, mme_loc_addr, ?EXP_ADDR_STR),
+    ?assertEqual(ExpData, s1ap_proxy:handle_pdu(OrigData)).
+
+
+%% [MME -> eNB] INITIAL CONTEXT SETUP RESPONSE
+initial_context_setup_rsp_pdu(TLA, TEID) when is_binary(TLA),
+                                              is_binary(TEID) ->
+    << 16#20, 16#09, 16#00, 16#22, 16#00, 16#00, 16#03, 16#00,
+       16#00, 16#40, 16#02, 16#00, 16#01, 16#00, 16#08, 16#40,
+       16#02, 16#00, 16#01, 16#00, 16#33, 16#40, 16#0f, 16#00,
+       16#00, 16#32, 16#40, 16#0a, 16#0a, 16#1f,
+       TLA/bytes, %% transportLayerAddress (IPv4)
+       TEID/bytes %% GTP-TEID
+    >>.
+
+initial_context_setup_rsp_test() ->
+    %% Original input data
+    TEID = << 16#00, 16#00, 16#00, 16#01 >>,
+    OrigTLA = << 16#c0, 16#a8, 16#02, 16#cb >>,
+    OrigData = initial_context_setup_rsp_pdu(OrigTLA, TEID),
+
+    %% Expected output data
+    ExpData = initial_context_setup_rsp_pdu(?EXP_ADDR_BIN, TEID),
+
+    application:set_env(osmo_s1gw, s1gw_bind_addr, ?EXP_ADDR_STR),
+    ?assertEqual(ExpData, s1ap_proxy:handle_pdu(OrigData)).
+
 %% vim:set ts=4 sw=4 et:
-- 
To view, visit https://gerrit.osmocom.org/c/erlang/osmo-s1gw/+/37104?usp=email
To unsubscribe, or for help writing mail filters, visit https://gerrit.osmocom.org/settings

Gerrit-Project: erlang/osmo-s1gw
Gerrit-Branch: master
Gerrit-Change-Id: Ia0d8f8d81756bcce5f518caee8887cf5822aaa08
Gerrit-Change-Number: 37104
Gerrit-PatchSet: 1
Gerrit-Owner: osmith osmith@sysmocom.de
Gerrit-Reviewer: Jenkins Builder
Gerrit-Reviewer: laforge laforge@osmocom.org
Gerrit-Reviewer: osmith osmith@sysmocom.de
Gerrit-CC: fixeria vyanitskiy@sysmocom.de
Gerrit-MessageType: merged



    