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-rw-r--r--lib/diameter/src/transport/diameter_sctp.erl272
1 files changed, 163 insertions, 109 deletions
diff --git a/lib/diameter/src/transport/diameter_sctp.erl b/lib/diameter/src/transport/diameter_sctp.erl
index 32e7aaca39..2c8d6f0a14 100644
--- a/lib/diameter/src/transport/diameter_sctp.erl
+++ b/lib/diameter/src/transport/diameter_sctp.erl
@@ -1,7 +1,7 @@
%%
%% %CopyrightBegin%
%%
-%% Copyright Ericsson AB 2010-2014. All Rights Reserved.
+%% Copyright Ericsson AB 2010-2015. All Rights Reserved.
%%
%% The contents of this file are subject to the Erlang Public License,
%% Version 1.1, (the "License"); you may not use this file except in
@@ -18,9 +18,11 @@
%%
-module(diameter_sctp).
-
-behaviour(gen_server).
+-compile({no_auto_import, [now/0]}).
+-import(diameter_lib, [now/0]).
+
%% interface
-export([start/3]).
@@ -37,7 +39,8 @@
code_change/3,
terminate/2]).
--export([info/1]). %% service_info callback
+-export([listener/1,%% diameter_sync callback
+ info/1]). %% service_info callback
-export([ports/0,
ports/1]).
@@ -99,22 +102,31 @@
-record(listener,
{ref :: reference(),
socket :: gen_sctp:sctp_socket(),
- count = 0 :: uint(),
+ count = 0 :: uint(), %% attached transport processes
tmap = ets:new(?MODULE, []) :: ets:tid(),
%% {MRef, Pid|AssocId}, {AssocId, Pid}
pending = {0, ets:new(?MODULE, [ordered_set])},
tref :: reference(),
accept :: [match()]}).
%% Field tmap is used to map an incoming message or event to the
-%% relevent transport process. Field pending implements a queue of
-%% transport processes to which an association has been assigned (at
-%% comm_up and written into tmap) but for which diameter hasn't yet
-%% spawned a transport process: a short-lived state of affairs as a
-%% new transport is spawned as a consequence of a peer being taken up,
-%% transport processes being spawned by the listener on demand. In
-%% case diameter starts a transport before comm_up on a new
-%% association, pending is set to an improper list with the spawned
-%% transport as head and the queue as tail.
+%% relevant transport process. Field pending implements two queues:
+%% the first of transport-to-be processes to which an association has
+%% been assigned (at comm_up and written into tmap) but for which
+%% diameter hasn't yet spawned a transport process, a short-lived
+%% state of affairs as a new transport is spawned as a consequence of
+%% a peer being taken up, transport processes being spawned by the
+%% listener on demand; the second of started transport processes that
+%% have not yet been assigned an association.
+%%
+%% When diameter calls start/3, the transport process is either taken
+%% from the first queue or spawned and placed in the second queue
+%% until an association is established. When an association is
+%% established, a controlling process is either taken from the second
+%% queue or spawned and placed in the first queue. Thus, there are
+%% only elements in one queue at a time, so share an ets table queue
+%% and tag it with a positive length if it contains the first queue, a
+%% negative length if it contains the second queue. The case -1 is
+%% handled differently for backwards compatibility reasons.
%% ---------------------------------------------------------------------------
%% # start/3
@@ -139,9 +151,9 @@ ip(T) ->
T.
%% A listener spawns transports either as a consequence of this call
-%% when there is not yet an association to associate with it, or at
-%% comm_up on a new association in which case the call retrieves a
-%% transport from the pending queue.
+%% when there is not yet an association to assign it, or at comm_up on
+%% a new association in which case the call retrieves a transport from
+%% the pending queue.
s({accept, Ref} = A, Addrs, Opts) ->
{LPid, LAs} = listener(Ref, {Opts, Addrs}),
try gen_server:call(LPid, {A, self()}, infinity) of
@@ -226,7 +238,7 @@ i({connect, Pid, Opts, Addrs, Ref}) ->
{LAs, Sock} = open(Addrs, Rest, 0),
putr(?REF_KEY, Ref),
proc_lib:init_ack({ok, self(), LAs}),
- erlang:monitor(process, Pid),
+ monitor(process, Pid),
#transport{parent = Pid,
mode = {connect, connect(Sock, RAs, RP, [])},
socket = Sock};
@@ -236,8 +248,8 @@ i({accept, Pid, LPid, Sock, Ref})
when is_pid(Pid) ->
putr(?REF_KEY, Ref),
proc_lib:init_ack({ok, self()}),
- erlang:monitor(process, Pid),
- erlang:monitor(process, LPid),
+ monitor(process, Pid),
+ monitor(process, LPid),
#transport{parent = Pid,
mode = {accept, LPid},
socket = Sock};
@@ -246,7 +258,7 @@ i({accept, Pid, LPid, Sock, Ref})
i({accept, Ref, LPid, Sock, Id}) ->
putr(?REF_KEY, Ref),
proc_lib:init_ack({ok, self()}),
- MRef = erlang:monitor(process, LPid),
+ MRef = monitor(process, LPid),
%% Wait for a signal that the transport has been started before
%% processing other messages.
receive
@@ -270,15 +282,23 @@ close(Sock, Id) ->
%% listener/2
+%% Accepting processes can be started concurrently: ensure only one
+%% listener is started.
listener(LRef, T) ->
+ diameter_sync:call({?MODULE, listener, LRef},
+ {?MODULE, listener, [{LRef, T}]},
+ infinity,
+ infinity).
+
+listener({LRef, T}) ->
l(diameter_reg:match({?MODULE, listener, {LRef, '_'}}), LRef, T).
-%% Existing process with the listening socket ...
+%% Existing listening process ...
l([{{?MODULE, listener, {_, AS}}, LPid}], _, _) ->
- {LAs, _Sock} = AS,
- {LPid, LAs};
-
-%% ... or not: start one.
+ {LAs, _Sock} = AS,
+ {LPid, LAs};
+
+%% ... or not.
l([], LRef, T) ->
{ok, LPid, LAs} = diameter_sctp_sup:start_child({listen, LRef, T}),
{LPid, LAs}.
@@ -347,11 +367,17 @@ type(T) ->
%% # handle_call/3
%% ---------------------------------------------------------------------------
+handle_call(T, From, #listener{pending = L} = S)
+ when is_list(L) ->
+ handle_call(T, From, upgrade(S));
+
handle_call({{accept, Ref}, Pid}, _, #listener{ref = Ref,
- count = N}
+ pending = {N,Q},
+ count = K}
= S) ->
- {TPid, NewS} = accept(Ref, Pid, S),
- {reply, {ok, TPid}, NewS#listener{count = N+1}};
+ TPid = accept(Ref, Pid, S),
+ {reply, {ok, TPid}, downgrade(S#listener{pending = {N-1,Q},
+ count = K+1})};
handle_call(_, _, State) ->
{reply, nok, State}.
@@ -370,8 +396,46 @@ handle_cast(_, State) ->
handle_info(T, #transport{} = S) ->
{noreply, #transport{} = t(T,S)};
+handle_info(T, #listener{pending = L} = S)
+ when is_list(L) ->
+ handle_info(T, upgrade(S));
+
handle_info(T, #listener{} = S) ->
- {noreply, #listener{} = l(T,S)}.
+ {noreply, downgrade(#listener{} = l(T,S))}.
+
+%% upgrade/1
+
+upgrade(#listener{pending = [TPid | {0,Q}]} = S) ->
+ ets:insert(Q, {TPid, now()}),
+ S#listener{pending = {-1,Q}}.
+%% Prior to the possiblity of setting pool_size on in transport
+%% configuration, a new accepting transport was only started following
+%% the death of a predecessor, so that there was only at most one
+%% previously started transport process waiting for an association.
+%% This assumption no longer holds with pool_size > 1, in which case
+%% several accepting transports are started concurrently. Deal with
+%% this by placing the started transports in a new queue of transport
+%% processes waiting for an association.
+%%
+%% Since only one of this queue and the existing queue of controlling
+%% processes waiting for a transport to be started can be non-empty at
+%% any given time, implement both queues in the same ets table. The
+%% absolute value of the first element of the 2-tuple is the queue
+%% length, the sign says which queue it is.
+
+%% downgrade/1
+%%
+%% Revert to the pre-pool_size representation when possible, for
+%% backwards compatibility in the case that the pool_size option
+%% hasn't been used.
+
+downgrade(#listener{pending = {-1,Q}} = S) ->
+ TPid = ets:first(Q),
+ ets:delete(Q, TPid),
+ S#listener{pending = [TPid | {0,Q}]};
+
+downgrade(S) ->
+ S.
%% ---------------------------------------------------------------------------
%% # code_change/3
@@ -436,54 +500,46 @@ l({sctp, Sock, _RA, _RP, Data} = Msg, #listener{socket = Sock} = S) ->
setopts(Sock)
end;
-%% Transport is asking message to be sent. See send/3 for why the send
-%% isn't directly from the transport.
-l({send, AssocId, StreamId, Bin}, #listener{socket = Sock} = S) ->
- send(Sock, AssocId, StreamId, Bin),
- S;
+l({'DOWN', MRef, process, TPid, _}, #listener{pending = {_,Q}} = S) ->
+ down(ets:member(Q, TPid), MRef, TPid, S);
+
+%% Timeout after the last accepting process has died.
+l({timeout, TRef, close = T}, #listener{tref = TRef,
+ count = 0}) ->
+ x(T);
+l({timeout, _, close}, #listener{} = S) ->
+ S.
+
+%% down/4
%% Accepting transport has died. One that's awaiting an association ...
-l({'DOWN', MRef, process, TPid, _}, #listener{pending = [TPid | Q],
- tmap = T,
- count = N}
- = S) ->
+down(true, MRef, TPid, #listener{pending = {N,Q},
+ tmap = T,
+ count = K}
+ = S)
+ when N < 0 ->
+ ets:delete(Q, TPid),
ets:delete(T, MRef),
ets:delete(T, TPid),
- start_timer(S#listener{count = N-1,
- pending = Q});
-
-%% ... ditto and a new transport has already been started ...
-l({'DOWN', _, process, _, _} = T, #listener{pending = [TPid | Q]}
- = S) ->
- #listener{pending = NQ}
- = NewS
- = l(T, S#listener{pending = Q}),
- NewS#listener{pending = [TPid | NQ]};
-
-%% ... or not.
-l({'DOWN', MRef, process, TPid, _}, #listener{socket = Sock,
- tmap = T,
- count = N,
- pending = {P,Q}}
- = S) ->
+ start_timer(S#listener{count = K-1,
+ pending = {N+1,Q}});
+
+%% ... or one that already has one.
+down(B, MRef, TPid, #listener{socket = Sock,
+ tmap = T,
+ count = K,
+ pending = {N,Q}}
+ = S) ->
[{MRef, Id}] = ets:lookup(T, MRef), %% Id = TPid | AssocId
ets:delete(T, MRef),
ets:delete(T, Id),
Id == TPid orelse close(Sock, Id),
- case ets:lookup(Q, TPid) of
- [{TPid, _}] -> %% transport in the pending queue ...
+ if B -> %% Waiting for attachment in the pending queue ...
ets:delete(Q, TPid),
- S#listener{pending = {P-1, Q}};
- [] -> %% ... or not
- start_timer(S#listener{count = N-1})
- end;
-
-%% Timeout after the last accepting process has died.
-l({timeout, TRef, close = T}, #listener{tref = TRef,
- count = 0}) ->
- x(T);
-l({timeout, _, close}, #listener{} = S) ->
- S.
+ S#listener{pending = {N-1,Q}};
+ true -> %% ... or already attached
+ start_timer(S#listener{count = K-1})
+ end.
%% t/2
%%
@@ -582,29 +638,24 @@ accept(Opts) ->
%% No pending associations: spawn a new transport.
accept(Ref, Pid, #listener{socket = Sock,
tmap = T,
- pending = {0,_} = Q}
- = S) ->
+ pending = {N,Q}})
+ when N =< 0 ->
Arg = {accept, Pid, self(), Sock, Ref},
{ok, TPid} = diameter_sctp_sup:start_child(Arg),
- MRef = erlang:monitor(process, TPid),
+ MRef = monitor(process, TPid),
ets:insert(T, [{MRef, TPid}, {TPid, MRef}]),
- {TPid, S#listener{pending = [TPid | Q]}};
-%% Placing the transport in the pending field makes it available to
-%% the next association. The stack starts a new accepting transport
-%% only after this one brings the connection up (or dies).
-
-%% Accepting transport has died. This can happen if a new transport is
-%% started before the DOWN has arrived.
-accept(Ref, Pid, #listener{pending = [TPid | {0,_} = Q]} = S) ->
- false = is_process_alive(TPid), %% assert
- accept(Ref, Pid, S#listener{pending = Q});
+ ets:insert(Q, {TPid, now()}),
+ TPid;
+%% Placing the transport in the second pending table makes it
+%% available to the next association.
%% Pending associations: attach to the first in the queue.
-accept(_, Pid, #listener{ref = Ref, pending = {N,Q}} = S) ->
+accept(_, Pid, #listener{ref = Ref,
+ pending = {_,Q}}) ->
TPid = ets:first(Q),
TPid ! {Ref, Pid},
ets:delete(Q, TPid),
- {TPid, S#listener{pending = {N-1, Q}}}.
+ TPid.
%% send/2
@@ -718,34 +769,12 @@ up(#transport{parent = Pid,
find(Id, Data, #listener{tmap = T} = S) ->
f(ets:lookup(T, Id), Data, S).
-%% New association and a transport waiting for one: use it.
-f([],
- {_, #sctp_assoc_change{state = comm_up,
- assoc_id = Id}},
- #listener{tmap = T,
- pending = [TPid | {_,_} = Q]}
- = S) ->
- [{TPid, MRef}] = ets:lookup(T, TPid),
- ets:insert(T, [{MRef, Id}, {Id, TPid}]),
- ets:delete(T, TPid),
- {TPid, S#listener{pending = Q}};
-
-%% New association and no transport start yet: spawn one and place it
-%% in the queue.
+%% New association ...
f([],
- {_, #sctp_assoc_change{state = comm_up,
- assoc_id = Id}},
- #listener{ref = Ref,
- socket = Sock,
- tmap = T,
- pending = {N,Q}}
+ {_, #sctp_assoc_change{state = comm_up, assoc_id = Id}},
+ #listener{pending = {N,Q}}
= S) ->
- Arg = {accept, Ref, self(), Sock, Id},
- {ok, TPid} = diameter_sctp_sup:start_child(Arg),
- MRef = erlang:monitor(process, TPid),
- ets:insert(T, [{MRef, Id}, {Id, TPid}]),
- ets:insert(Q, {TPid, now()}),
- {TPid, S#listener{pending = {N+1, Q}}};
+ {find(Id, S), S#listener{pending = {N+1,Q}}};
%% Known association ...
f([{_, TPid}], _, S) ->
@@ -755,6 +784,31 @@ f([{_, TPid}], _, S) ->
f([], _, _) ->
false.
+%% find/2
+
+%% Transport waiting for an association: use it.
+find(Id, #listener{tmap = T,
+ pending = {N,Q}})
+ when N < 0 ->
+ TPid = ets:first(Q),
+ [{TPid, MRef}] = ets:lookup(T, TPid),
+ ets:insert(T, [{MRef, Id}, {Id, TPid}]),
+ ets:delete(T, TPid),
+ ets:delete(Q, TPid),
+ TPid;
+
+%% No transport start yet: spawn one and queue.
+find(Id, #listener{ref = Ref,
+ socket = Sock,
+ tmap = T,
+ pending = {_,Q}}) ->
+ Arg = {accept, Ref, self(), Sock, Id},
+ {ok, TPid} = diameter_sctp_sup:start_child(Arg),
+ MRef = monitor(process, TPid),
+ ets:insert(T, [{MRef, Id}, {Id, TPid}]),
+ ets:insert(Q, {TPid, now()}),
+ TPid.
+
%% assoc_id/1
assoc_id({[#sctp_sndrcvinfo{assoc_id = Id}], _}) ->