[M] Change in ...osmo-epdg[master]: Forward PGW Address HSS->AAA->ePDG - gerrit-log

4 Mar 2024

pespin has uploaded this change for review. ( https://gerrit.osmocom.org/c/erlang/osmo-epdg/+/36158?usp=email )
Change subject: Forward PGW Address HSS->AAA->ePDG
......................................................................
Forward PGW Address HSS->AAA->ePDG
Use subscriber information provided by AAA & HSS regarding PDN-GW
address when creating the S2b session.
Related: OS#6384
Change-Id: I83a68271ee6548e0e32fc9f0cab385bad5852388
---
M src/aaa_diameter_swm.erl
M src/aaa_diameter_swx_cb.erl
M src/aaa_ue_fsm.erl
M src/epdg_gtpc_s2b.erl
M src/epdg_ue_fsm.erl
5 files changed, 122 insertions(+), 27 deletions(-)
git pull ssh://gerrit.osmocom.org:29418/erlang/osmo-epdg refs/changes/58/36158/1

diff --git a/src/aaa_diameter_swm.erl b/src/aaa_diameter_swm.erl
index 7fdc247..0e3fa45 100644
--- a/src/aaa_diameter_swm.erl
+++ b/src/aaa_diameter_swm.erl
@@ -67,7 +67,8 @@
    #swm_session{imsi = Imsi} ->
    	aaa_ue_fsm:ev_swm_auth_compl(Sess#swm_session.pid, Apn);
    undefined ->
-		epdg_diameter_swm:auth_compl_response(Imsi, {error, imsi_unknown})
+		RC_USER_UNKNOWN=5030,
+		epdg_diameter_swm:auth_compl_response(Imsi, {error, RC_USER_UNKNOWN})
    end,
    {noreply, State};
diff --git a/src/aaa_diameter_swx_cb.erl b/src/aaa_diameter_swx_cb.erl
index bf4a79e..5dd00ef 100644
--- a/src/aaa_diameter_swx_cb.erl
+++ b/src/aaa_diameter_swx_cb.erl
@@ -77,7 +77,18 @@
     #'SAR'{'Server-Assignment-Type' = SAType} = Request,
     % Retrieve fields from answer:
     #'SAA'{'Result-Code' = [ResultCode]} = Msg,
-    aaa_ue_fsm:ev_rx_swx_saa(ReqPid, {SAType, ResultCode}),
+    case result_code_success(ResultCode) of
+    ok ->
+        #'SAA'{'Non-3GPP-User-Data' = N3UA} = Msg,
+        PGWAddresses = parse_pgw_addr_from_N3UA(N3UA),
+        case PGWAddresses of
+        undefined -> ResInfo = #{};
+        _ -> ResInfo = maps:put(pgw_address_list, PGWAddresses, #{})
+        end,
+        aaa_ue_fsm:ev_rx_swx_saa(ReqPid, {ok, SAType, ResInfo});
+    _ ->
+        aaa_ue_fsm:ev_rx_swx_saa(ReqPid, {error, SAType, ResultCode})
+    end,
     {ok, Msg}.
 handle_answer(#diameter_packet{msg = Msg, errors = []}, _Request, _SvcName, Peer) ->
     lager:info("SWx Rx ~p: ~p~n", [Peer, Msg]),
@@ -101,3 +112,33 @@
 %% handle_request/3
 handle_request(_Packet, _SvcName, _Peer) ->
     erlang:error({unexpected, ?MODULE, ?LINE}).
+
+%% ------------------------------------------------------------------
+%% Internal Function Definitions
+%% ------------------------------------------------------------------
+
+result_code_success(2001) -> ok;
+result_code_success(2002) -> ok;
+result_code_success(_) -> invalid_result_code.
+
+parse_pgw_addr_from_MIP6_Agent_Info([]) ->
+    undefined;
+parse_pgw_addr_from_MIP6_Agent_Info([AgentInfo]) ->
+    #'MIP6-Agent-Info'{'MIP-Home-Agent-Address' = AgentAddrOpt} = AgentInfo,
+    case AgentAddrOpt of
+    [] -> undefined;
+    Res -> Res
+    end.
+parse_pgw_addr_from_APN_Configuration([]) ->
+    undefined;
+parse_pgw_addr_from_APN_Configuration([Head | Tail] = _ApnConfigs) ->
+    #'APN-Configuration'{'MIP6-Agent-Info' = AgentInfoOpt} = Head,
+    case parse_pgw_addr_from_MIP6_Agent_Info(AgentInfoOpt) of
+    undefined -> parse_pgw_addr_from_APN_Configuration(Tail);
+    Res -> Res
+    end.
+parse_pgw_addr_from_N3UA([]) ->
+    undefined;
+parse_pgw_addr_from_N3UA([N3UA]) ->
+    #'Non-3GPP-User-Data'{'APN-Configuration' = ApnConfigs} = N3UA,
+    parse_pgw_addr_from_APN_Configuration(ApnConfigs).
\ No newline at end of file
diff --git a/src/aaa_ue_fsm.erl b/src/aaa_ue_fsm.erl
index 7f70005..fd39061 100644
--- a/src/aaa_ue_fsm.erl
+++ b/src/aaa_ue_fsm.erl
@@ -102,10 +102,10 @@
                 {error, Err}
         end.
-ev_rx_swx_saa(Pid, {SAType, ResultCode}) ->
+ev_rx_swx_saa(Pid, Result) ->
         lager:info("ue_fsm ev_rx_swx_saa~n", []),
         try
-                gen_statem:call(Pid, {rx_swx_saa, SAType, ResultCode})
+                gen_statem:call(Pid, {rx_swx_saa, Result})
         catch
         exit:Err ->
                 {error, Err}
@@ -181,11 +181,16 @@
 state_wait_swx_saa(enter, _OldState, Data) ->
         {keep_state, Data};
-state_wait_swx_saa({call, From}, {rx_swx_saa, _SAType, ResultCode}, Data) ->
-        lager:info("ue_fsm state_wait_swx_saa event=rx_swx_saa, ~p~n", [Data]),
-        aaa_diameter_swm:auth_compl_response(Data#ue_fsm_data.imsi, {ok, ResultCode}),
-        % TODO: don't transit if SAS returned error code.
-        {next_state, state_authenticated, Data, [{reply,From,ok}]}.
+state_wait_swx_saa({call, From}, {rx_swx_saa, Result}, Data) ->
+        lager:info("ue_fsm state_wait_swx_saa event=rx_swx_saa ~p, ~p~n", [Result, Data]),
+        case Result of
+        {error, _SAType, ResultCode} ->
+                aaa_diameter_swm:auth_compl_response(Data#ue_fsm_data.imsi, {error, ResultCode}),
+                {next_state, state_new, Data, [{reply,From,ok}]};
+        {ok, _SAType, ResInfo} ->
+                aaa_diameter_swm:auth_compl_response(Data#ue_fsm_data.imsi, {ok, ResInfo}),
+                {next_state, state_authenticated, Data, [{reply,From,ok}]}
+        end.
state_authenticated(enter, _OldState, Data) ->
         % Mark ePDG session as active:
@@ -256,7 +261,11 @@
 state_authenticated_wait_swx_saa(enter, _OldState, Data) ->
         {keep_state, Data};
-state_authenticated_wait_swx_saa({call, From}, {rx_swx_saa, SAType, ResultCode}, Data) ->
+state_authenticated_wait_swx_saa({call, From}, {rx_swx_saa, Result}, Data) ->
+        case Result of
+        {error, SAType, ResultCode} -> ResultCode;
+        {ok, SAType, _ResInfo} -> ResultCode = 2001
+        end,
         lager:info("ue_fsm state_authenticated_wait_swx_saa event=rx_swx_saa SAType=~p ResulCode=~p, ~p~n", [SAType, ResultCode, Data]),
         case SAType of
         ?'DIAMETER_CX_SERVER-ASSIGNMENT-TYPE_PGW_UPDATE' ->
diff --git a/src/epdg_gtpc_s2b.erl b/src/epdg_gtpc_s2b.erl
index b0a34bd..a8a42a2 100644
--- a/src/epdg_gtpc_s2b.erl
+++ b/src/epdg_gtpc_s2b.erl
@@ -48,7 +48,7 @@
 %% gen_server Function Exports
 -export([init/1, handle_call/3, handle_cast/2, handle_info/2]).
 -export([code_change/3]).
--export([create_session_req/3, delete_session_req/1]).
+-export([create_session_req/4, delete_session_req/1]).
%% Application Definitions
 -define(SERVER, ?MODULE).
@@ -88,6 +88,8 @@
     imsi                   :: binary(),
     pid                    :: pid(),
     apn                    :: binary(),
+    raddr_str              :: string(),
+    raddr                  :: inet:ip_address(),
     ue_ip                  :: inet:ip_address(),
     local_control_tei = 0  :: non_neg_integer(),
     remote_control_tei = 0 :: non_neg_integer(),
@@ -142,15 +144,21 @@
             lager:error("GTPv2C UDP socket open error: ~w~n", [Reason])
     end.
-create_session_req(Imsi, Apn, APCO) ->
-    gen_server:call(?SERVER, {gtpc_create_session_req, {Imsi, Apn, APCO}}).
+create_session_req(Imsi, Apn, APCO, PGWAddrCandidateList) ->
+    gen_server:call(?SERVER, {gtpc_create_session_req, {Imsi, Apn, APCO, PGWAddrCandidateList}}).
delete_session_req(Imsi) ->
     gen_server:call(?SERVER, {gtpc_delete_session_req, {Imsi}}).
-handle_call({gtpc_create_session_req, {Imsi, Apn, APCO}}, {Pid, _Tag} = _From, State0) ->
+handle_call({gtpc_create_session_req, {Imsi, Apn, APCO, PGWAddrCandidateList}}, {Pid, _Tag} = _From, State0) ->
+    RemoteAddrStr = pick_gtpc_remote_address(PGWAddrCandidateList, State0),
+    lager:debug("Selected PGW Remote Address ~p~n", [RemoteAddrStr]),
+    {ok, RemoteAddrInet} = inet_parse:address(RemoteAddrStr),
     {Sess0, State1} = find_or_new_gtp_session(Imsi,
-                        #gtp_session{pid = Pid, apn = list_to_binary(Apn)},
+                        #gtp_session{pid = Pid,
+                                     apn = list_to_binary(Apn),
+                                     raddr_str = RemoteAddrInet,
+                                     raddr = RemoteAddrInet},
                         State0),
     Req = gen_create_session_request(Sess0, APCO, State1),
     tx_gtp(Req, State1),
@@ -352,6 +360,16 @@
     find_unused_local_teid(State, State#gtp_state.next_local_data_tei,
                            dec_tei(State#gtp_state.next_local_data_tei)).
+pick_gtpc_remote_address(PGWAddrCandidateList, State) ->
+    case PGWAddrCandidateList of
+    [] ->
+        %% Pick default address from configuration:
+        State#gtp_state .raddr_str;
+    [Head|_Tail] ->
+        % TODO: pick a compatible address with .laddr from PGWAddrCandidateList is exists.
+        Head
+    end.
+
 %% connect/2
 connect(Name, {Socket, RemoteAddr, RemotePort}) ->
     lager:info("~s connecting to IP ~s port ~p~n", [Name, RemoteAddr, RemotePort]),
diff --git a/src/epdg_ue_fsm.erl b/src/epdg_ue_fsm.erl
index 291df26..c6358fd 100644
--- a/src/epdg_ue_fsm.erl
+++ b/src/epdg_ue_fsm.erl
@@ -53,10 +53,11 @@
-record(ue_fsm_data, {
         imsi,
-        apn = "internet" :: string(),
-        tun_pdp_ctx :: epdg_tun_pdp_ctx,
-        tear_down_gsup_needed = false :: boolean(), %% need to send GSUP PurgeMSResp after STR+STA?
-        tear_down_gsup_cause = 0 :: integer()
+        apn                     = "internet"    :: string(),
+        pgw_rem_addr_list       = []            :: list(),
+        tun_pdp_ctx                             :: epdg_tun_pdp_ctx,
+        tear_down_gsup_needed   = false         :: boolean(), %% need to send GSUP PurgeMSResp after STR+STA?
+        tear_down_gsup_cause    = 0             :: integer()
         }).
get_server_name_by_imsi(Imsi) ->
@@ -236,13 +237,22 @@
         lager:info("ue_fsm state_authenticating event=lu_request, ~p, ~p~n", [Result, Data]),
         % Rx "GSUP CEAI LU Req" is our way of saying Rx "Swm Diameter-EAP REQ (DER) with EAP AVP containing successuful auth":
         case Result of
-                {ok, _} ->
-                        Ret = ok;
-                {error, Err} ->
-                        Ret = {error, Err}
-        end,
-        gsup_server:lu_response(Data#ue_fsm_data.imsi, Ret),
-        {next_state, state_authenticated, Data, [{reply,From,Ret}]}.
+        {ok, ResInfo} ->
+                % Store PGW Remote address if AAA/HSS signalled them to us:
+                case maps:find(pdp_info_list, ResInfo) of
+                error ->
+                        Data1 = Data;
+                PGWAddrCandidateList ->
+                        Data1 = Data#ue_fsm_data{pgw_rem_addr_list = PGWAddrCandidateList}
+                end,
+                Ret = ok,
+                gsup_server:lu_response(Data1#ue_fsm_data.imsi, Ret),
+                {next_state, state_authenticated, Data1, [{reply,From,Ret}]};
+        {error, Err} ->
+                Ret = {error, Err},
+                gsup_server:lu_response(Data#ue_fsm_data.imsi, Ret),
+                {next_state, state_new, Data, [{reply,From,Ret}]}
+        end.
state_authenticated(enter, _OldState, Data) ->
         {keep_state, Data};
@@ -253,7 +263,10 @@
state_authenticated({call, From}, {tunnel_request, PCO}, Data) ->
         lager:info("ue_fsm state_authenticated event=tunnel_request, ~p~n", [Data]),
-        epdg_gtpc_s2b:create_session_req(Data#ue_fsm_data.imsi, Data#ue_fsm_data.apn, PCO),
+        epdg_gtpc_s2b:create_session_req(Data#ue_fsm_data.imsi,
+                                         Data#ue_fsm_data.apn,
+                                         PCO,
+                                         Data#ue_fsm_data.pgw_rem_addr_list),
         {next_state, state_wait_create_session_resp, Data, [{reply,From,ok}]};
state_authenticated({call, From}, purge_ms_request, Data) ->
-- 
To view, visit https://gerrit.osmocom.org/c/erlang/osmo-epdg/+/36158?usp=email
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Gerrit-Project: erlang/osmo-epdg
Gerrit-Branch: master
Gerrit-Change-Id: I83a68271ee6548e0e32fc9f0cab385bad5852388
Gerrit-Change-Number: 36158
Gerrit-PatchSet: 1
Gerrit-Owner: pespin pespin@sysmocom.de
Gerrit-MessageType: newchange



    