%%
%% %CopyrightBegin%
%%
%% Copyright Ericsson AB 1999-2016. All Rights Reserved.
%%
%% Licensed under the Apache License, Version 2.0 (the "License");
%% you may not use this file except in compliance with the License.
%% You may obtain a copy of the License at
%%
%% http://www.apache.org/licenses/LICENSE-2.0
%%
%% Unless required by applicable law or agreed to in writing, software
%% distributed under the License is distributed on an "AS IS" BASIS,
%% WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
%% See the License for the specific language governing permissions and
%% limitations under the License.
%%
%% %CopyrightEnd%
%%
%%%----------------------------------------------------------------------
%%% Purpose : The handshake of a streamed distribution connection
%%% in a separate file to make it usable for other
%%% distribution protocols.
%%%----------------------------------------------------------------------
-module(dist_util).
%%-compile(export_all).
-export([handshake_we_started/1, handshake_other_started/1,
start_timer/1, setup_timer/2,
reset_timer/1, cancel_timer/1,
shutdown/3, shutdown/4]).
-import(error_logger,[error_msg/2]).
-include("dist_util.hrl").
-include("dist.hrl").
-ifdef(DEBUG).
-define(shutdown_trace(A,B), io:format(A,B)).
-else.
-define(shutdown_trace(A,B), noop).
-endif.
-define(to_port(FSend, Socket, Data),
case FSend(Socket, Data) of
{error, closed} ->
self() ! {tcp_closed, Socket},
{error, closed};
R ->
R
end).
-define(int16(X), [((X) bsr 8) band 16#ff, (X) band 16#ff]).
-define(int32(X),
[((X) bsr 24) band 16#ff, ((X) bsr 16) band 16#ff,
((X) bsr 8) band 16#ff, (X) band 16#ff]).
-define(i16(X1,X0),
(?u16(X1,X0) -
(if (X1) > 127 -> 16#10000; true -> 0 end))).
-define(u16(X1,X0),
(((X1) bsl 8) bor (X0))).
-define(u32(X3,X2,X1,X0),
(((X3) bsl 24) bor ((X2) bsl 16) bor ((X1) bsl 8) bor (X0))).
-record(tick, {read = 0,
write = 0,
tick = 0,
ticked = 0
}).
remove_flag(Flag, Flags) ->
case Flags band Flag of
0 ->
Flags;
_ ->
Flags - Flag
end.
adjust_flags(ThisFlags, OtherFlags) ->
case (?DFLAG_PUBLISHED band ThisFlags) band OtherFlags of
0 ->
{remove_flag(?DFLAG_PUBLISHED, ThisFlags),
remove_flag(?DFLAG_PUBLISHED, OtherFlags)};
_ ->
{ThisFlags, OtherFlags}
end.
publish_flag(hidden, _) ->
0;
publish_flag(_, OtherNode) ->
case net_kernel:publish_on_node(OtherNode) of
true ->
?DFLAG_PUBLISHED;
_ ->
0
end.
make_this_flags(RequestType, OtherNode) ->
publish_flag(RequestType, OtherNode) bor
%% The parenthesis below makes the compiler generate better code.
(?DFLAG_EXPORT_PTR_TAG bor
?DFLAG_EXTENDED_PIDS_PORTS bor
?DFLAG_EXTENDED_REFERENCES bor
?DFLAG_DIST_MONITOR bor
?DFLAG_FUN_TAGS bor
?DFLAG_DIST_MONITOR_NAME bor
?DFLAG_HIDDEN_ATOM_CACHE bor
?DFLAG_NEW_FUN_TAGS bor
?DFLAG_BIT_BINARIES bor
?DFLAG_NEW_FLOATS bor
?DFLAG_UNICODE_IO bor
?DFLAG_DIST_HDR_ATOM_CACHE bor
?DFLAG_SMALL_ATOM_TAGS bor
?DFLAG_UTF8_ATOMS bor
?DFLAG_MAP_TAG bor
?DFLAG_BIG_CREATION).
handshake_other_started(#hs_data{request_type=ReqType}=HSData0) ->
{PreOtherFlags,Node,Version} = recv_name(HSData0),
PreThisFlags = make_this_flags(ReqType, Node),
{ThisFlags, OtherFlags} = adjust_flags(PreThisFlags,
PreOtherFlags),
HSData = HSData0#hs_data{this_flags=ThisFlags,
other_flags=OtherFlags,
other_version=Version,
other_node=Node,
other_started=true},
check_dflags(HSData),
is_allowed(HSData),
?debug({"MD5 connection from ~p (V~p)~n",
[Node, HSData#hs_data.other_version]}),
mark_pending(HSData),
{MyCookie,HisCookie} = get_cookies(Node),
ChallengeA = gen_challenge(),
send_challenge(HSData, ChallengeA),
reset_timer(HSData#hs_data.timer),
ChallengeB = recv_challenge_reply(HSData, ChallengeA, MyCookie),
send_challenge_ack(HSData, gen_digest(ChallengeB, HisCookie)),
?debug({dist_util, self(), accept_connection, Node}),
connection(HSData);
handshake_other_started(OldHsData) when element(1,OldHsData) =:= hs_data ->
handshake_other_started(convert_old_hsdata(OldHsData)).
%%
%% check if connecting node is allowed to connect
%% with allow-node-scheme
%%
is_allowed(#hs_data{other_node = Node,
allowed = Allowed} = HSData) ->
case lists:member(Node, Allowed) of
false when Allowed =/= [] ->
send_status(HSData, not_allowed),
error_msg("** Connection attempt from "
"disallowed node ~w ** ~n", [Node]),
?shutdown2(Node, {is_allowed, not_allowed});
_ -> true
end.
%%
%% Check that both nodes can handle the same types of extended
%% node containers. If they can not, abort the connection.
%%
check_dflags(#hs_data{other_node = Node,
other_flags = OtherFlags,
other_started = OtherStarted} = HSData) ->
Mandatory = [{?DFLAG_EXTENDED_REFERENCES, "EXTENDED_REFERENCES"},
{?DFLAG_EXTENDED_PIDS_PORTS, "EXTENDED_PIDS_PORTS"}],
Missing = lists:filtermap(fun({Bit, Str}) ->
case Bit band OtherFlags of
Bit -> false;
0 -> {true, Str}
end
end,
Mandatory),
case Missing of
[] ->
ok;
_ ->
case OtherStarted of
true ->
send_status(HSData, not_allowed),
Dir = "from",
How = "rejected";
_ ->
Dir = "to",
How = "aborted"
end,
error_msg("** ~w: Connection attempt ~s node ~w ~s "
"since it cannot handle ~p."
"**~n", [node(), Dir, Node, How, Missing]),
?shutdown2(Node, {check_dflags_failed, Missing})
end.
%% No nodedown will be sent if we fail before this process has
%% succeeded to mark the node as pending.
mark_pending(#hs_data{kernel_pid=Kernel,
other_node=Node,
this_node=MyNode}=HSData) ->
case do_mark_pending(Kernel, MyNode, Node,
(HSData#hs_data.f_address)(HSData#hs_data.socket,
Node),
HSData#hs_data.other_flags) of
ok ->
send_status(HSData, ok),
reset_timer(HSData#hs_data.timer);
ok_pending ->
send_status(HSData, ok_simultaneous),
reset_timer(HSData#hs_data.timer);
nok_pending ->
send_status(HSData, nok),
?shutdown(Node);
up_pending ->
%% Check if connection is still alive, no
%% implies that the connection is no longer pending
%% due to simultaneous connect
do_alive(HSData),
%% This can happen if the other node goes down,
%% and goes up again and contact us before we have
%% detected that the socket was closed.
wait_pending(Kernel),
reset_timer(HSData#hs_data.timer);
already_pending ->
%% FIXME: is this a case ?
?debug({dist_util,self(),mark_pending,already_pending,Node}),
?shutdown(Node)
end.
%%
%% Marking pending and negotiating away
%% simultaneous connection problems
%%
wait_pending(Kernel) ->
receive
{Kernel, pending} ->
?trace("wait_pending returned for pid ~p.~n",
[self()]),
ok
end.
do_alive(#hs_data{other_node = Node} = HSData) ->
send_status(HSData, alive),
case recv_status(HSData) of
true -> true;
false -> ?shutdown(Node)
end.
do_mark_pending(Kernel, MyNode, Node, Address, Flags) ->
Kernel ! {self(), {accept_pending,MyNode,Node,Address,
publish_type(Flags)}},
receive
{Kernel,{accept_pending,Ret}} ->
?trace("do_mark_pending(~p,~p,~p,~p) -> ~p~n",
[Kernel,Node,Address,Flags,Ret]),
Ret
end.
is_pending(Kernel, Node) ->
Kernel ! {self(), {is_pending, Node}},
receive
{Kernel, {is_pending, Reply}} -> Reply
end.
%%
%% This will tell the net_kernel about the nodedown as it
%% recognizes the exit signal.
%% The termination of this process does also imply that the Socket
%% is closed in a controlled way by inet_drv.
%%
-spec shutdown(atom(), non_neg_integer(), term()) -> no_return().
shutdown(Module, Line, Data) ->
shutdown(Module, Line, Data, shutdown).
-spec shutdown(atom(), non_neg_integer(), term(), term()) -> no_return().
shutdown(_Module, _Line, _Data, Reason) ->
?shutdown_trace("Net Kernel 2: shutting down connection "
"~p:~p, data ~p,reason ~p~n",
[_Module,_Line, _Data, Reason]),
flush_down(),
exit(Reason).
%% Use this line to debug connection.
%% Set net_kernel verbose = 1 as well.
%% exit({Reason, ?MODULE, _Line, _Data, erlang:timestamp()}).
flush_down() ->
receive
{From, get_status} ->
From ! {self(), get_status, error},
flush_down()
after 0 ->
ok
end.
handshake_we_started(#hs_data{request_type=ReqType,
other_node=Node}=PreHSData) ->
PreThisFlags = make_this_flags(ReqType, Node),
HSData = PreHSData#hs_data{this_flags=PreThisFlags},
send_name(HSData),
recv_status(HSData),
{PreOtherFlags,ChallengeA} = recv_challenge(HSData),
{ThisFlags,OtherFlags} = adjust_flags(PreThisFlags, PreOtherFlags),
NewHSData = HSData#hs_data{this_flags = ThisFlags,
other_flags = OtherFlags,
other_started = false},
check_dflags(NewHSData),
MyChallenge = gen_challenge(),
{MyCookie,HisCookie} = get_cookies(Node),
send_challenge_reply(NewHSData,MyChallenge,
gen_digest(ChallengeA,HisCookie)),
reset_timer(NewHSData#hs_data.timer),
recv_challenge_ack(NewHSData, MyChallenge, MyCookie),
connection(NewHSData);
handshake_we_started(OldHsData) when element(1,OldHsData) =:= hs_data ->
handshake_we_started(convert_old_hsdata(OldHsData)).
convert_old_hsdata({hs_data, KP, ON, TN, S, T, TF, A, OV, OF, OS, FS, FR,
FS_PRE, FS_POST, FG, FA, MFT, MFG, RT}) ->
#hs_data{
kernel_pid = KP, other_node = ON, this_node = TN, socket = S, timer = T,
this_flags = TF, allowed = A, other_version = OV, other_flags = OF,
other_started = OS, f_send = FS, f_recv = FR, f_setopts_pre_nodeup = FS_PRE,
f_setopts_post_nodeup = FS_POST, f_getll = FG, f_address = FA,
mf_tick = MFT, mf_getstat = MFG, request_type = RT}.
%% --------------------------------------------------------------
%% The connection has been established.
%% --------------------------------------------------------------
connection(#hs_data{other_node = Node,
socket = Socket,
f_address = FAddress,
f_setopts_pre_nodeup = FPreNodeup,
f_setopts_post_nodeup = FPostNodeup}= HSData) ->
cancel_timer(HSData#hs_data.timer),
PType = publish_type(HSData#hs_data.other_flags),
case FPreNodeup(Socket) of
ok ->
do_setnode(HSData), % Succeeds or exits the process.
Address = FAddress(Socket,Node),
mark_nodeup(HSData,Address),
case FPostNodeup(Socket) of
ok ->
con_loop({HSData#hs_data.kernel_pid,
Node,
Socket,
PType,
HSData#hs_data.mf_tick,
HSData#hs_data.mf_getstat,
HSData#hs_data.mf_setopts,
HSData#hs_data.mf_getopts},
#tick{});
_ ->
?shutdown2(Node, connection_setup_failed)
end;
_ ->
?shutdown(Node)
end.
%% Generate a message digest from Challenge number and Cookie
gen_digest(Challenge, Cookie) when is_integer(Challenge), is_atom(Cookie) ->
erlang:md5([atom_to_list(Cookie)|integer_to_list(Challenge)]).
%% ---------------------------------------------------------------
%% Challenge code
%% gen_challenge() returns a "random" number
%% ---------------------------------------------------------------
gen_challenge() ->
A = erlang:phash2([erlang:node()]),
B = erlang:monotonic_time(),
C = erlang:unique_integer(),
{D,_} = erlang:statistics(reductions),
{E,_} = erlang:statistics(runtime),
{F,_} = erlang:statistics(wall_clock),
{G,H,_} = erlang:statistics(garbage_collection),
%% A(8) B(16) C(16)
%% D(16),E(8), F(16) G(8) H(16)
( ((A bsl 24) + (E bsl 16) + (G bsl 8) + F) bxor
(B + (C bsl 16)) bxor
(D + (H bsl 16)) ) band 16#ffffffff.
%%
%% Get the cookies for a node from auth
%%
get_cookies(Node) ->
case auth:get_cookie(Node) of
X when is_atom(X) ->
{X,X}
% {Y,Z} when is_atom(Y), is_atom(Z) ->
% {Y,Z};
% _ ->
% erlang:error("Corrupt cookie database")
end.
%% No error return; either succeeds or terminates the process.
do_setnode(#hs_data{other_node = Node, socket = Socket,
other_flags = Flags, other_version = Version,
f_getll = GetLL}) ->
case GetLL(Socket) of
{ok,Port} ->
?trace("setnode(md5,~p ~p ~p)~n",
[Node, Port, {publish_type(Flags),
'(', Flags, ')',
Version}]),
case (catch
erlang:setnode(Node, Port,
{Flags, Version, '', ''})) of
{'EXIT', {system_limit, _}} ->
error_msg("** Distribution system limit reached, "
"no table space left for node ~w ** ~n",
[Node]),
?shutdown(Node);
{'EXIT', Other} ->
exit(Other);
_Else ->
ok
end;
_ ->
error_msg("** Distribution connection error, "
"could not get low level port for node ~w ** ~n",
[Node]),
?shutdown(Node)
end.
mark_nodeup(#hs_data{kernel_pid = Kernel,
other_node = Node,
other_flags = Flags,
other_started = OtherStarted},
Address) ->
Kernel ! {self(), {nodeup,Node,Address,publish_type(Flags),
true}},
receive
{Kernel, inserted} ->
ok;
{Kernel, bad_request} ->
TypeT = case OtherStarted of
true ->
"accepting connection";
_ ->
"initiating connection"
end,
error_msg("Fatal: ~p was not allowed to "
"send {nodeup, ~p} to kernel when ~s~n",
[self(), Node, TypeT]),
?shutdown(Node)
end.
con_loop({Kernel, Node, Socket, Type, MFTick, MFGetstat, MFSetOpts, MFGetOpts}=ConData,
Tick) ->
receive
{tcp_closed, Socket} ->
?shutdown2(Node, connection_closed);
{Kernel, disconnect} ->
?shutdown2(Node, disconnected);
{Kernel, aux_tick} ->
case MFGetstat(Socket) of
{ok, _, _, PendWrite} ->
send_tick(Socket, PendWrite, MFTick);
_ ->
ignore_it
end,
con_loop(ConData, Tick);
{Kernel, tick} ->
case send_tick(Socket, Tick, Type,
MFTick, MFGetstat) of
{ok, NewTick} ->
con_loop(ConData, NewTick);
{error, not_responding} ->
error_msg("** Node ~p not responding **~n"
"** Removing (timedout) connection **~n",
[Node]),
?shutdown2(Node, net_tick_timeout);
_Other ->
?shutdown2(Node, send_net_tick_failed)
end;
{From, get_status} ->
case MFGetstat(Socket) of
{ok, Read, Write, _} ->
From ! {self(), get_status, {ok, Read, Write}},
con_loop(ConData, Tick);
_ ->
?shutdown2(Node, get_status_failed)
end;
{From, Ref, {setopts, Opts}} ->
Ret = case MFSetOpts of
undefined -> {error, enotsup};
_ -> MFSetOpts(Socket, Opts)
end,
From ! {Ref, Ret},
con_loop(ConData, Tick);
{From, Ref, {getopts, Opts}} ->
Ret = case MFGetOpts of
undefined -> {error, enotsup};
_ -> MFGetOpts(Socket, Opts)
end,
From ! {Ref, Ret},
con_loop(ConData, Tick)
end.
%% ------------------------------------------------------------
%% Misc. functions.
%% ------------------------------------------------------------
send_name(#hs_data{socket = Socket, this_node = Node,
f_send = FSend,
this_flags = Flags,
other_version = Version}) ->
?trace("send_name: node=~w, version=~w\n",
[Node,Version]),
?to_port(FSend, Socket,
[$n, ?int16(Version), ?int32(Flags), atom_to_list(Node)]).
send_challenge(#hs_data{socket = Socket, this_node = Node,
other_version = Version,
this_flags = Flags,
f_send = FSend},
Challenge ) ->
?trace("send: challenge=~w version=~w\n",
[Challenge,Version]),
?to_port(FSend, Socket, [$n,?int16(Version), ?int32(Flags),
?int32(Challenge),
atom_to_list(Node)]).
send_challenge_reply(#hs_data{socket = Socket, f_send = FSend},
Challenge, Digest) ->
?trace("send_reply: challenge=~w digest=~p\n",
[Challenge,Digest]),
?to_port(FSend, Socket, [$r,?int32(Challenge),Digest]).
send_challenge_ack(#hs_data{socket = Socket, f_send = FSend},
Digest) ->
?trace("send_ack: digest=~p\n", [Digest]),
?to_port(FSend, Socket, [$a,Digest]).
%%
%% Get the name of the other side.
%% Close the connection if invalid data.
%% The IP address sent is not interesting (as in the old
%% tcp_drv.c which used it to detect simultaneous connection
%% attempts).
%%
recv_name(#hs_data{socket = Socket, f_recv = Recv}) ->
case Recv(Socket, 0, infinity) of
{ok,Data} ->
get_name(Data);
_ ->
?shutdown(no_node)
end.
get_name([$n,VersionA, VersionB, Flag1, Flag2, Flag3, Flag4 | OtherNode]) ->
{?u32(Flag1, Flag2, Flag3, Flag4), list_to_atom(OtherNode),
?u16(VersionA,VersionB)};
get_name(Data) ->
?shutdown(Data).
publish_type(Flags) ->
case Flags band ?DFLAG_PUBLISHED of
0 ->
hidden;
_ ->
normal
end.
%% wait for challenge after connect
recv_challenge(#hs_data{socket=Socket,other_node=Node,
other_version=Version,f_recv=Recv}) ->
case Recv(Socket, 0, infinity) of
{ok,[$n,V1,V0,Fl1,Fl2,Fl3,Fl4,CA3,CA2,CA1,CA0 | Ns]} ->
Flags = ?u32(Fl1,Fl2,Fl3,Fl4),
try {list_to_existing_atom(Ns),?u16(V1,V0)} of
{Node,Version} ->
Challenge = ?u32(CA3,CA2,CA1,CA0),
?trace("recv: node=~w, challenge=~w version=~w\n",
[Node, Challenge,Version]),
{Flags,Challenge};
_ ->
?shutdown2(no_node, {recv_challenge_failed, no_node, Ns})
catch
error:badarg ->
?shutdown2(no_node, {recv_challenge_failed, no_node, Ns})
end;
Other ->
?shutdown2(no_node, {recv_challenge_failed, Other})
end.
%%
%% wait for challenge response after send_challenge
%%
recv_challenge_reply(#hs_data{socket = Socket,
other_node = NodeB,
f_recv = FRecv},
ChallengeA, Cookie) ->
case FRecv(Socket, 0, infinity) of
{ok,[$r,CB3,CB2,CB1,CB0 | SumB]} when length(SumB) =:= 16 ->
SumA = gen_digest(ChallengeA, Cookie),
ChallengeB = ?u32(CB3,CB2,CB1,CB0),
?trace("recv_reply: challenge=~w digest=~p\n",
[ChallengeB,SumB]),
?trace("sum = ~p\n", [SumA]),
case list_to_binary(SumB) of
SumA ->
ChallengeB;
_ ->
error_msg("** Connection attempt from "
"disallowed node ~w ** ~n", [NodeB]),
?shutdown2(NodeB, {recv_challenge_reply_failed, bad_cookie})
end;
Other ->
?shutdown2(no_node, {recv_challenge_reply_failed, Other})
end.
recv_challenge_ack(#hs_data{socket = Socket, f_recv = FRecv,
other_node = NodeB},
ChallengeB, CookieA) ->
case FRecv(Socket, 0, infinity) of
{ok,[$a|SumB]} when length(SumB) =:= 16 ->
SumA = gen_digest(ChallengeB, CookieA),
?trace("recv_ack: digest=~p\n", [SumB]),
?trace("sum = ~p\n", [SumA]),
case list_to_binary(SumB) of
SumA ->
ok;
_ ->
error_msg("** Connection attempt to "
"disallowed node ~w ** ~n", [NodeB]),
?shutdown2(NodeB, {recv_challenge_ack_failed, bad_cookie})
end;
Other ->
?shutdown2(NodeB, {recv_challenge_ack_failed, Other})
end.
recv_status(#hs_data{kernel_pid = Kernel, socket = Socket,
other_node = Node, f_recv = Recv} = HSData) ->
case Recv(Socket, 0, infinity) of
{ok, [$s|StrStat]} ->
Stat = list_to_atom(StrStat),
?debug({dist_util,self(),recv_status, Node, Stat}),
case Stat of
not_allowed -> ?shutdown2(Node, {recv_status_failed, not_allowed});
nok ->
%% wait to be killed by net_kernel
receive
after infinity -> ok
end;
alive ->
Reply = is_pending(Kernel, Node),
?debug({is_pending,self(),Reply}),
send_status(HSData, Reply),
if not Reply ->
?shutdown(Node);
Reply ->
Stat
end;
_ -> Stat
end;
Error ->
?debug({dist_util,self(),recv_status_error,
Node, Error}),
?shutdown2(Node, {recv_status_failed, Error})
end.
send_status(#hs_data{socket = Socket, other_node = Node,
f_send = FSend}, Stat) ->
?debug({dist_util,self(),send_status, Node, Stat}),
case FSend(Socket, [$s | atom_to_list(Stat)]) of
{error, _} ->
?shutdown(Node);
_ ->
true
end.
%%
%% Send a TICK to the other side.
%%
%% This will happen every 15 seconds (by default)
%% The idea here is that every 15 secs, we write a little
%% something on the connection if we haven't written anything for
%% the last 15 secs.
%% This will ensure that nodes that are not responding due to
%% hardware errors (Or being suspended by means of ^Z) will
%% be considered to be down. If we do not want to have this
%% we must start the net_kernel (in erlang) without its
%% ticker process, In that case this code will never run
%% And then every 60 seconds we also check the connection and
%% close it if we havn't received anything on it for the
%% last 60 secs. If ticked == tick we havn't received anything
%% on the connection the last 60 secs.
%% The detection time interval is thus, by default, 45s < DT < 75s
%% A HIDDEN node is always (if not a pending write) ticked if
%% we haven't read anything as a hidden node only ticks when it receives
%% a TICK !!
send_tick(Socket, Tick, Type, MFTick, MFGetstat) ->
#tick{tick = T0,
read = Read,
write = Write,
ticked = Ticked} = Tick,
T = T0 + 1,
T1 = T rem 4,
case MFGetstat(Socket) of
{ok, Read, _, _} when Ticked =:= T ->
{error, not_responding};
{ok, Read, W, Pend} when Type =:= hidden ->
send_tick(Socket, Pend, MFTick),
{ok, Tick#tick{write = W + 1,
tick = T1}};
{ok, Read, Write, Pend} ->
send_tick(Socket, Pend, MFTick),
{ok, Tick#tick{write = Write + 1,
tick = T1}};
{ok, R, Write, Pend} ->
send_tick(Socket, Pend, MFTick),
{ok, Tick#tick{write = Write + 1,
read = R,
tick = T1,
ticked = T}};
{ok, Read, W, _} ->
{ok, Tick#tick{write = W,
tick = T1}};
{ok, R, W, _} ->
{ok, Tick#tick{write = W,
read = R,
tick = T1,
ticked = T}};
Error ->
Error
end.
send_tick(Socket, 0, MFTick) ->
MFTick(Socket);
send_tick(_, _Pend, _) ->
%% Dont send tick if pending write.
ok.
%% ------------------------------------------------------------
%% Connection setup timeout timer.
%% After Timeout milliseconds this process terminates
%% which implies that the owning setup/accept process terminates.
%% The timer is reset before every network operation during the
%% connection setup !
%% ------------------------------------------------------------
start_timer(Timeout) ->
spawn_link(?MODULE, setup_timer, [self(), Timeout*?trace_factor]).
setup_timer(Pid, Timeout) ->
receive
{Pid, reset} ->
setup_timer(Pid, Timeout)
after Timeout ->
?trace("Timer expires ~p, ~p~n",[Pid, Timeout]),
?shutdown2(timer, setup_timer_timeout)
end.
reset_timer(Timer) ->
Timer ! {self(), reset},
ok.
cancel_timer(Timer) ->
unlink(Timer),
exit(Timer, shutdown).
