pespin has uploaded this change for review. ( https://gerrit.osmocom.org/c/erlang/osmo-epdg/+/35949?usp=email )

Change subject: s2b: Take unused local TEIC/TEID when new one is needed ......................................................................

s2b: Take unused local TEIC/TEID when new one is needed

Change-Id: I7262402d14fc53ff17c4000cef385136b8de7e55 --- M src/epdg_gtpc_s2b.erl 1 file changed, 78 insertions(+), 9 deletions(-)

git pull ssh://gerrit.osmocom.org:29418/erlang/osmo-epdg refs/changes/49/35949/1

diff --git a/src/epdg_gtpc_s2b.erl b/src/epdg_gtpc_s2b.erl index 95c4d10..e795cd2 100644 --- a/src/epdg_gtpc_s2b.erl +++ b/src/epdg_gtpc_s2b.erl @@ -70,9 +70,9 @@ raddr :: inet:ip_address(), rport :: non_neg_integer(), restart_counter :: 0..255, - seq_no :: 0..16#ffffffff, - next_local_control_tei = 1 :: 0..16#ffffffff, - next_local_data_tei = 1 :: 0..16#ffffffff, + seq_no :: 0..16#ffffff, + next_local_control_tei :: 0..16#ffffffff, + next_local_data_tei :: 0..16#ffffffff, sessions = sets:new() :: sets:set() }).

@@ -128,7 +128,9 @@ raddr = RemoteAddrInet, rport = RemotePort, restart_counter = 0, - seq_no = 0 + seq_no = rand:uniform(16#FFFFFF), + next_local_control_tei = rand:uniform(16#FFFFFFFE), + next_local_data_tei = rand:uniform(16#FFFFFFFE) }, {ok, St}; {error, Reason} -> @@ -203,19 +205,27 @@ NewSeqNr = State#gtp_state.seq_no +1, State#gtp_state{seq_no = NewSeqNr}.

+% Skip 0 +inc_tei(Tei) when Tei >= 16#FFFFFFFE -> 16#00000001; +% Skip 0xffffffff +inc_tei(Tei) -> (Tei + 1) rem 16#FFFFFFFF. + +% Skip 0, 0xffffffff +dec_tei(Tei) when Tei =< 1 -> 16#FFFFFFFE; +dec_tei(Tei) -> (Tei - 1) rem 16#FFFFFFFF. + new_gtp_session(Imsi, SessTpl, State) -> - % TODO: find non-used local TEI inside State DefaultBearer = #gtp_bearer{ ebi = 5, - local_data_tei = State#gtp_state.next_local_data_tei + local_data_tei = find_unused_local_teid(State) }, Sess = SessTpl#gtp_session{imsi = Imsi, - local_control_tei = State#gtp_state.next_local_control_tei, + local_control_tei = find_unused_local_teic(State), default_bearer_id = DefaultBearer#gtp_bearer.ebi, bearers = sets:add_element(DefaultBearer, sets:new()) }, - NewSt = State#gtp_state{next_local_control_tei = State#gtp_state.next_local_control_tei + 1, - next_local_data_tei = State#gtp_state.next_local_data_tei + 1, + NewSt = State#gtp_state{next_local_control_tei = inc_tei(Sess#gtp_session.local_control_tei), + next_local_data_tei = inc_tei(DefaultBearer#gtp_bearer.local_data_tei), sessions = sets:add_element(Sess, State#gtp_state.sessions)}, {Sess, NewSt}.

@@ -256,6 +266,15 @@ Sess#gtp_session.bearers), Res.

+gtp_session_find_bearer_by_local_teid(Sess, LocalTEID) -> + {LocalTEID, Res} = sets:fold( + fun(BearerIt = #gtp_bearer{ebi = LookupLocalTEID}, {LookupLocalTEID, _AccIn}) -> {LookupLocalTEID, BearerIt}; + (_, AccIn) -> AccIn + end, + {LocalTEID, undefined}, + Sess#gtp_session.bearers), + Res. + gtp_session_add_bearer(Sess, Bearer) -> lager:debug("Add bearer ~p to session ~p~n", [Bearer, Sess]), Sess#gtp_session{bearers = sets:add_element(Bearer, Sess#gtp_session.bearers)}. @@ -286,6 +305,47 @@ State#gtp_state.sessions), Res.

+% returns Sess if found, undefined it not +find_gtp_session_by_local_teid(LocalControlTeid, State) -> + {LocalControlTeid, Res} = sets:fold( + fun(SessIt = #gtp_session{}, {LookupLTEID, AccIn}) -> + case gtp_session_find_bearer_by_local_teid(SessIt, LookupLTEID) of + undefined -> {LookupLTEID, AccIn}; + _ -> {LookupLTEID, SessIt} + end + end, + {LocalControlTeid, undefined}, + State#gtp_state.sessions), + Res. + +find_unused_local_teic(State, TeicEnd, TeicEnd) -> + case find_gtp_session_by_local_teic(TeicEnd, State) of + undefined -> TeicEnd; + _ -> undefined + end; +find_unused_local_teic(State, TeicIt, TeicEnd) -> + case find_gtp_session_by_local_teic(TeicIt, State) of + undefined -> TeicIt; + _ -> find_unused_local_teic(State, inc_tei(TeicIt), TeicEnd) + end. +find_unused_local_teic(State) -> + find_unused_local_teic(State, State#gtp_state.next_local_control_tei, + dec_tei(State#gtp_state.next_local_control_tei)). + +find_unused_local_teid(State, TeidEnd, TeidEnd) -> + case find_gtp_session_by_local_teid(TeidEnd, State) of + undefined -> TeidEnd; + _ -> undefined + end; +find_unused_local_teid(State, TeidIt, TeidEnd) -> + case find_gtp_session_by_local_teid(TeidIt, State) of + undefined -> TeidIt; + _ -> find_unused_local_teid(State, inc_tei(TeidIt), TeidEnd) + end. +find_unused_local_teid(State) -> + find_unused_local_teid(State, State#gtp_state.next_local_data_tei, + dec_tei(State#gtp_state.next_local_data_tei)). + %% connect/2 connect(Name, {Socket, RemoteAddr, RemotePort}) -> lager:info("~s connecting to IP ~s port ~p~n", [Name, RemoteAddr, RemotePort]),