pespin submitted this change.
Handle GSUP EPDG_Tunnel through GTPv2C CreateSession Req+Resp
Initial GTPv2C infrastructure to send GTPv2C CreateSession Request upon
receival of GSUP EPDG_Tunnel Request, and answer with EPDG_Tunnel
Resp/err when creating the session fails.
Related: OS#6046
Change-Id: I6f00b7fce2d5fcdc484bfd45629b9141f16bc579
---
M config/sys.config
M rebar.config
M rebar.lock
A src/epdg_gtpc_s2b.erl
M src/gsup_server.erl
M src/osmo_epdg.app.src
M src/osmo_epdg_sup.erl
7 files changed, 320 insertions(+), 7 deletions(-)
diff --git a/config/sys.config b/config/sys.config
index 8d751b9..1b89e86 100755
--- a/config/sys.config
+++ b/config/sys.config
@@ -13,7 +13,13 @@
{vendor_id, 0},
{origin_host, "epdg.localdomain"},
{origin_realm, "localdomain"},
- {context_id, "epdg@localdomain"}]},
+ {context_id, "epdg@localdomain"},
+ % GTPv2C Connection parameters
+ {gtpc_local_ip, "127.0.0.2"},
+ {gtpc_local_port, 2123},
+ {gtpc_remote_ip, "127.0.0.1"},
+ {gtpc_remote_port, 2123}
+ ]},
%% ===========================================
%% SASL config
%% ===========================================
diff --git a/rebar.config b/rebar.config
index 03e0e7c..d834c32 100644
--- a/rebar.config
+++ b/rebar.config
@@ -4,6 +4,7 @@
{deps, [
{lager, {git, "https://github.com/erlang-lager/lager", {tag, "3.9.2"}}},
+ {gtplib, "3.2.0"},
{osmo_ss7, {git, "https://gitea.osmocom.org/erlang/osmo_ss7", {ref, "9f294d3612f998860004820d1d85b4264721577b"}}},
{osmo_gsup, {git, "https://gitea.osmocom.org/erlang/osmo_gsup", {ref, "07672d8ab1608aa9c9e50ca035521876558fcd42"}}}
]}.
diff --git a/rebar.lock b/rebar.lock
index 4aeafea..8f00ea6 100644
--- a/rebar.lock
+++ b/rebar.lock
@@ -1,16 +1,18 @@
{"1.2.0",
-[{<<"epcap">>,
+[{<<"cut">>,{pkg,<<"cut">>,<<"1.0.3">>},1},
+ {<<"epcap">>,
{git,"https://github.com/msantos/epcap",
{ref,"d5c03caf608c1369e68cfed0a606d3eb82ddfd21"}},
1},
{<<"goldrush">>,{pkg,<<"goldrush">>,<<"0.1.9">>},1},
+ {<<"gtplib">>,{pkg,<<"gtplib">>,<<"3.2.0">>},0},
{<<"lager">>,
{git,"https://github.com/erlang-lager/lager",
{ref,"459a3b2cdd9eadd29e5a7ce5c43932f5ccd6eb88"}},
0},
{<<"osmo_gsup">>,
{git,"https://gitea.osmocom.org/erlang/osmo_gsup",
- {ref,"07672d8ab1608aa9c9e50ca035521876558fcd42"}},
+ {ref,"e23f118e6e8f7ee1247db34e4cb79e4cecdb0947"}},
0},
{<<"osmo_ss7">>,
{git,"https://gitea.osmocom.org/erlang/osmo_ss7",
@@ -23,10 +25,17 @@
{<<"pkt">>,
{git,"https://github.com/msantos/pkt",
{ref,"67a4a14f596fded5ad5f2d8f94318faa8ad2c288"}},
- 1}]}.
+ 1},
+ {<<"ppplib">>,{pkg,<<"ppplib">>,<<"1.0.0">>},1}]}.
[
{pkg_hash,[
- {<<"goldrush">>, <<"F06E5D5F1277DA5C413E84D5A2924174182FB108DABB39D5EC548B27424CD106">>}]},
+ {<<"cut">>, <<"1577F2F3BC0F2BF3B97903B7426F8A3D79523687B6A444D0F59A095EF69A0E81">>},
+ {<<"goldrush">>, <<"F06E5D5F1277DA5C413E84D5A2924174182FB108DABB39D5EC548B27424CD106">>},
+ {<<"gtplib">>, <<"41E8E14BE21DD6E08B2CBB9D708BCF8FDD47CA49D7FFA480219CAB29F5AE2760">>},
+ {<<"ppplib">>, <<"F9EC2690532BAF590277A305A2276FCFAD0285557E1055552F8A2FCAF1BF081A">>}]},
{pkg_hash_ext,[
- {<<"goldrush">>, <<"99CB4128CFFCB3227581E5D4D803D5413FA643F4EB96523F77D9E6937D994CEB">>}]}
+ {<<"cut">>, <<"1A4A25DB2B7C5565FD28B314A4EEB898B1ED3CAFFA1AB09149345FB5731ED04B">>},
+ {<<"goldrush">>, <<"99CB4128CFFCB3227581E5D4D803D5413FA643F4EB96523F77D9E6937D994CEB">>},
+ {<<"gtplib">>, <<"264626E6993C17B00CA3C083B9BF23D16B88BEEDDDE35F62C954832C21B57AEF">>},
+ {<<"ppplib">>, <<"32440D630F55DD29F849847DD8F15F69175FDDC210AA88517AC8AD2854CD6FA1">>}]}
].
diff --git a/src/epdg_gtpc_s2b.erl b/src/epdg_gtpc_s2b.erl
new file mode 100644
index 0000000..82985a5
--- /dev/null
+++ b/src/epdg_gtpc_s2b.erl
@@ -0,0 +1,252 @@
+% S2b: GTPv2C towards PGW
+%
+% 3GPP TS 29.274
+%
+% (C) 2023 by sysmocom - s.f.m.c. GmbH <info@sysmocom.de>
+% Author: Pau Espin Pedrol <pespin@sysmocom.de>
+%
+% All Rights Reserved
+%
+% This program is free software; you can redistribute it and/or modify
+% it under the terms of the GNU Affero General Public License as
+% published by the Free Software Foundation; either version 3 of the
+% License, or (at your option) any later version.
+%
+% This program is distributed in the hope that it will be useful,
+% but WITHOUT ANY WARRANTY; without even the implied warranty of
+% MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
+% GNU General Public License for more details.
+%
+% You should have received a copy of the GNU Affero General Public License
+% along with this program. If not, see <http://www.gnu.org/licenses/>.
+%
+% Additional Permission under GNU AGPL version 3 section 7:
+%
+% If you modify this Program, or any covered work, by linking or
+% combining it with runtime libraries of Erlang/OTP as released by
+% Ericsson on http://www.erlang.org (or a modified version of these
+% libraries), containing parts covered by the terms of the Erlang Public
+% License (http://www.erlang.org/EPLICENSE), the licensors of this
+% Program grant you additional permission to convey the resulting work
+% without the need to license the runtime libraries of Erlang/OTP under
+% the GNU Affero General Public License. Corresponding Source for a
+% non-source form of such a combination shall include the source code
+% for the parts of the runtime libraries of Erlang/OTP used as well as
+% that of the covered work.
+
+
+-module(epdg_gtpc_s2b).
+-author('Pau Espin Pedrol <pespin@sysmocom.de>').
+
+-behaviour(gen_server).
+
+-include_lib("gtplib/include/gtp_packet.hrl").
+
+%% API Function Exports
+-export([start_link/5]).
+-export([terminate/2]).
+%% gen_server Function Exports
+-export([init/1, handle_call/3, handle_cast/2, handle_info/2]).
+-export([code_change/3]).
+-export([create_session_req/1]).
+
+%% Application Definitions
+-define(SERVER, ?MODULE).
+-define(SVC_NAME, ?MODULE).
+-define(APP_ALIAS, ?MODULE).
+-define(CALLBACK_MOD, epdg_gtpc_s2b_cb).
+-define(ENV_APP_NAME, osmo_epdg).
+
+%% TODO: make APN configurable? get it from HSS?
+-define(APN, <<"internet">>).
+
+-record(gtp_state, {
+ socket,
+ laddr_str,
+ laddr :: inet:ip_address(),
+ lport :: non_neg_integer(),
+ raddr_str,
+ raddr :: inet:ip_address(),
+ rport :: non_neg_integer(),
+ restart_counter :: 0..255,
+ seq_no :: 0..16#ffffffff,
+ sess_list %% TODO: fill it, list of gtp_session
+}).
+
+-record(gtp_bearer, {
+ ebi :: non_neg_integer(),
+ local_data_tei = 0 :: non_neg_integer(),
+ remote_data_tei = 0 :: non_neg_integer()
+}).
+
+-record(gtp_session, {
+ imsi :: binary(),
+ apn :: binary(),
+ ue_ip :: inet:ip_address(),
+ local_control_tei = 0 :: non_neg_integer(),
+ remote_control_tei = 0 :: non_neg_integer(),
+ bearer :: gtp_bearer %% FIXME: only one bearer for now
+}).
+
+start_link(LocalAddr, LocalPort, RemoteAddr, RemotePort, Options) ->
+ gen_server:start_link({local, ?SERVER}, ?MODULE, [LocalAddr, LocalPort, RemoteAddr, RemotePort, Options], []).
+
+peer_down(API, SvcName, {PeerRef, _} = Peer) ->
+ % fixme: why do we still have ets here?
+ (catch ets:delete(?MODULE, {API, PeerRef})),
+ gen_server:cast(?SERVER, {peer_down, SvcName, Peer}),
+ ok.
+
+init(State) ->
+ lager:info("epdg_gtpc_s2b: init(): ~p", [State]),
+ [LocalAddr | [LocalPort | [RemoteAddr | [RemotePort | _]]]] = State,
+ lager:info("epdg_gtpc_s2b: Binding to IP ~s port ~p~n", [LocalAddr, LocalPort]),
+ {ok, LocalAddrInet} = inet_parse:address(LocalAddr),
+ {ok, RemoteAddrInet} = inet_parse:address(RemoteAddr),
+ Opts = [
+ binary,
+ {ip, LocalAddrInet},
+ {active, true},
+ {reuseaddr, true}
+ ],
+ Ret = gen_udp:open(LocalPort, Opts),
+ case Ret of
+ {ok, Socket} ->
+ lager:info("epdg_gtpc_s2b: Socket is ~p~n", [Socket]),
+ ok = connect({Socket, RemoteAddr, RemotePort}),
+ St = #gtp_state{
+ socket = Socket,
+ laddr_str = LocalAddr,
+ laddr = LocalAddrInet,
+ lport = LocalPort,
+ raddr_str = RemoteAddr,
+ raddr = RemoteAddrInet,
+ rport = RemotePort,
+ restart_counter = 0,
+ seq_no = 0
+ },
+ {ok, St};
+ {error, Reason} ->
+ lager:error("GTPv2C UDP socket open error: ~w~n", [Reason])
+ end.
+
+create_session_req(Imsi) ->
+ gen_server:call(?SERVER,
+ {gtpc_create_session_req, {Imsi}}).
+
+handle_call({gtpc_create_session_req, {Imsi}}, _From, State) ->
+ Sess = new_gtp_session(Imsi, State),
+ Req = gen_create_session_request(Sess, State),
+ %TODO: increment State.seq_no.
+ tx_gtp(Req, State),
+ lager:debug("Waiting for CreateSessionResponse~n", []),
+ receive
+ {udp, _Socket, IP, InPortNo, RxMsg} ->
+ try
+ Resp = gtp_packet:decode(RxMsg),
+ logger:info("s2b: Rx from IP ~p port ~n ~p~n", [IP, InPortNo, Resp]),
+ %% TODO: store Sess in State.
+ {reply, {ok, Resp}, State}
+ catch Any ->
+ logger:error("Error sending message to receiver, ERROR: ~p~n", [Any]),
+ {reply, {error, decode_failure}, State}
+ end
+ after 5000 ->
+ logger:error("Timeout waiting for CreateSessionResponse for ~p~n", [Req]),
+ {reply, timeout, State}
+ end.
+
+%% @callback gen_server
+handle_cast(stop, State) ->
+ {stop, normal, State};
+handle_cast(_Req, State) ->
+ {noreply, State}.
+
+%% @callback gen_server
+handle_info(_Info, State) ->
+ {noreply, State}.
+
+%% @callback gen_server
+code_change(_OldVsn, State, _Extra) ->
+ {ok, State}.
+
+%% @callback gen_server
+terminate(normal, State) ->
+ udp_gen:close(State#gtp_state.socket),
+ ok;
+terminate(shutdown, _State) ->
+ ok;
+terminate({shutdown, _Reason}, _State) ->
+ ok;
+terminate(_Reason, _State) ->
+ ok.
+
+%% ------------------------------------------------------------------
+%% Internal Function Definitions
+%% ------------------------------------------------------------------
+
+%% connect/2
+connect(Name, {Socket, RemoteAddr, RemotePort}) ->
+ lager:info("~s connecting to IP ~s port ~p~n", [Name, RemoteAddr, RemotePort]),
+ gen_udp:connect(Socket, RemoteAddr, RemotePort).
+
+connect(Address) ->
+ connect(?SVC_NAME, Address).
+
+tx_gtp(Req, State) ->
+ lager:info("s2b: Tx ~p~n", [Req]),
+ Msg = gtp_packet:encode(Req),
+ gen_udp:send(State#gtp_state.socket, State#gtp_state.raddr, State#gtp_state.rport, Msg).
+
+new_gtp_session(Imsi, _State) ->
+ % TODO: find non-used local TEI inside State
+ Bearer = #gtp_bearer{
+ ebi = 5,
+ local_data_tei = 1
+ },
+ #gtp_session{imsi = Imsi,
+ apn = ?APN,
+ local_control_tei = 0,
+ bearer = Bearer
+ }.
+
+%% 7.2.1 Create Session Request
+gen_create_session_request(#gtp_session{imsi = Imsi,
+ apn = Apn,
+ local_control_tei = LocalCtlTEI,
+ bearer = Bearer},
+ #gtp_state{laddr = LocalAddr,
+ restart_counter = RCnt,
+ seq_no = SeqNo}) ->
+ BearersIE = [#v2_bearer_level_quality_of_service{
+ pci = 1, pl = 10, pvi = 0, label = 8,
+ maximum_bit_rate_for_uplink = 0,
+ maximum_bit_rate_for_downlink = 0,
+ guaranteed_bit_rate_for_uplink = 0,
+ guaranteed_bit_rate_for_downlink = 0
+ },
+ #v2_eps_bearer_id{eps_bearer_id = Bearer#gtp_bearer.ebi},
+ #v2_fully_qualified_tunnel_endpoint_identifier{
+ instance = 0,
+ interface_type = 31, %% "S2b-U ePDG GTP-U"
+ key = Bearer#gtp_bearer.local_data_tei,
+ ipv4 = LocalAddr
+ }
+ ],
+ IEs = [#v2_recovery{restart_counter = RCnt},
+ #v2_international_mobile_subscriber_identity{imsi = Imsi},
+ #v2_rat_type{rat_type = 3}, %% 3 = WLAN
+ #v2_fully_qualified_tunnel_endpoint_identifier{
+ instance = Bearer#gtp_bearer.ebi,
+ interface_type = 30, %% "S2b ePDG GTP-C"
+ key = LocalCtlTEI,
+ ipv4 = LocalAddr
+ },
+ #v2_access_point_name{instance = 0, apn = [Apn]},
+ #v2_selection_mode{mode = 0},
+ #v2_pdn_address_allocation{type = ipv4, address = <<0,0,0,0>>},
+ #v2_bearer_context{group = BearersIE}
+ ],
+ #gtp{version = v2, type = create_session_request, tei = 0, seq_no = SeqNo, ie = IEs}.
+
+
diff --git a/src/gsup_server.erl b/src/gsup_server.erl
index 923d020..14d2364 100644
--- a/src/gsup_server.erl
+++ b/src/gsup_server.erl
@@ -177,6 +177,23 @@
% epdg tunnel request / trigger the establishment to the PGW and prepares everything for the user traffic to flow
% When sending a epdg_tunnel_response everything must be ready for the UE traffic
handle_info({ipa, Socket, ?IPAC_PROTO_EXT_GSUP, GsupMsgRx = #{message_type := epdg_tunnel_request, imsi := Imsi}}, S) ->
+ lager:info("GSUP: Rx ~p~n", [GsupMsgRx]),
+ Result = epdg_gtpc_s2b:create_session_req(Imsi),
+ case Result of
+ {ok, _} ->
+ Resp = #{message_type => epdg_tunnel_result,
+ imsi => Imsi,
+ message_class => 5
+ };
+ {error, _} ->
+ Resp = #{message_type => epdg_tunnel_error,
+ imsi => Imsi,
+ message_class => 5,
+ cause => 16#11 % FIXME: Use proper defines as cause code and use Network failure
+ }
+ end,
+ lager:info("GSUP: Tx ~p~n", [Resp]),
+ ipa_proto:send(Socket, ?IPAC_PROTO_EXT_GSUP, Resp),
{noreply, S};
handle_info(Info, S) ->
diff --git a/src/osmo_epdg.app.src b/src/osmo_epdg.app.src
index 483d339..ec60bd2 100644
--- a/src/osmo_epdg.app.src
+++ b/src/osmo_epdg.app.src
@@ -8,6 +8,7 @@
kernel,
stdlib,
lager,
+ gtplib,
diameter,
osmo_gsup,
osmo_ss7
diff --git a/src/osmo_epdg_sup.erl b/src/osmo_epdg_sup.erl
index 457d993..c679b39 100644
--- a/src/osmo_epdg_sup.erl
+++ b/src/osmo_epdg_sup.erl
@@ -8,6 +8,10 @@
-define(ENV_APP_NAME, osmo_epdg).
-define(ENV_DEFAULT_GSUP_LOCAL_IP, "0.0.0.0").
-define(ENV_DEFAULT_GSUP_LOCAL_PORT, 4222).
+-define(ENV_DEFAULT_GTPC_LOCAL_IP, "127.0.0.2").
+-define(ENV_DEFAULT_GTPC_LOCAL_PORT, 2123).
+-define(ENV_DEFAULT_GTPC_REMOTE_IP, "127.0.0.1").
+-define(ENV_DEFAULT_GTPC_REMOTE_PORT, 2123).
start_link() ->
supervisor:start_link({local, ?SERVER}, ?MODULE, []).
@@ -15,11 +19,20 @@
init([]) ->
GsupLocalIp = application:get_env(?ENV_APP_NAME, gsup_local_ip, ?ENV_DEFAULT_GSUP_LOCAL_IP),
GsupLocalPort = application:get_env(?ENV_APP_NAME, gsup_local_port, ?ENV_DEFAULT_GSUP_LOCAL_PORT),
+ GtpcLocalIp = application:get_env(?ENV_APP_NAME, gtpc_local_ip, ?ENV_DEFAULT_GTPC_LOCAL_IP),
+ GtpcLocalPort = application:get_env(?ENV_APP_NAME, gtpc_local_port, ?ENV_DEFAULT_GTPC_LOCAL_PORT),
+ GtpcRemoteIp = application:get_env(?ENV_APP_NAME, gtpc_remote_ip, ?ENV_DEFAULT_GTPC_REMOTE_IP),
+ GtpcRemotePort = application:get_env(?ENV_APP_NAME, gtpc_remote_port, ?ENV_DEFAULT_GTPC_REMOTE_PORT),
DiaServer = {epdg_diameter_swx, {epdg_diameter_swx,start_link,[]},
permanent,
5000,
worker,
[epdg_diameter_swx_cb]},
+ GtpcServer = {epdg_gtpc_s2b, {epdg_gtpc_s2b,start_link, [GtpcLocalIp, GtpcLocalPort, GtpcRemoteIp, GtpcRemotePort, []]},
+ permanent,
+ 5000,
+ worker,
+ [epdg_gtpc_s2b]},
GsupServer = {gsup_server, {gsup_server, start_link, [GsupLocalIp, GsupLocalPort, []]},
permanent,
5000,
@@ -30,4 +43,4 @@
5000,
worker,
[auth_handler]},
- {ok, { {one_for_all, 5, 10}, [DiaServer, GsupServer, AuthHandler]} }.
+ {ok, { {one_for_all, 5, 10}, [DiaServer, GtpcServer, GsupServer, AuthHandler]} }.
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