1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33
34
35
36
37
38
39
40
41
42
43
44
45
46
47
48
49
50
51
52
53
54
55
56
57
58
59
60
61
62
63
64
65
66
67
68
69
70
71
72
73
74
75
76
77
78
79
80
81
82
83
84
85
86
87
88
89
90
91
92
93
94
95
96
97
98
99
100
101
102
103
104
105
106
107
108
109
110
111
112
113
114
115
116
117
118
119
120
121
122
123
124
125
126
127
128
129
130
131
132
133
134
135
136
137
138
139
140
141
142
143
144
145
146
147
148
149
150
151
152
153
154
155
156
157
158
159
160
161
162
163
164
165
166
167
168
169
170
171
172
173
174
175
176
177
178
179
180
181
182
183
184
185
186
187
188
189
190
191
192
193
194
195
196
197
198
199
200
201
202
203
204
205
206
207
208
209
210
211
212
213
214
215
216
217
218
219
220
221
222
223
224
225
226
227
228
229
230
231
232
233
234
235
236
237
238
239
240
241
242
243
244
245
246
247
248
249
250
251
252
253
254
255
256
257
258
259
260
261
262
263
264
265
266
267
268
269
270
271
272
273
274
275
276
277
278
279
280
281
282
283
284
285
286
287
288
289
290
291
292
293
294
295
296
297
298
299
300
301
302
303
304
305
306
307
308
309
310
311
312
313
314
315
316
317
318
319
320
321
322
323
324
325
326
327
328
329
330
331
332
333
334
335
336
337
338
339
340
341
342
343
344
345
346
347
348
349
350
351
352
353
354
355
356
357
358
359
360
361
362
363
364
365
366
367
368
369
370
371
372
373
374
375
376
377
378
379
380
381
382
383
384
385
386
387
388
389
390
391
392
393
394
395
396
397
398
399
400
401
402
403
404
405
406
407
408
409
410
411
412
413
414
415
416
417
418
419
420
421
422
423
424
425
426
427
428
429
430
431
432
433
434
435
436
437
438
439
440
441
442
443
444
445
446
447
448
449
450
451
452
453
454
455
456
457
458
459
460
461
462
463
464
465
466
467
468
469
470
471
472
473
474
475
476
477
478
479
480
481
482
483
484
485
486
487
488
489
490
491
492
493
494
495
496
497
498
499
500
501
502
503
504
505
506
507
508
509
510
511
512
513
514
515
516
517
518
519
520
521
522
523
524
525
526
527
528
529
530
531
532
533
534
535
536
537
538
539
540
541
542
543
544
545
546
547
548
549
550
551
552
553
554
555
556
557
558
559
560
561
562
563
564
565
566
567
568
569
570
571
572
573
574
575
576
577
578
579
580
581
582
583
584
585
586
587
588
589
590
591
592
593
594
595
596
597
598
599
600
601
602
603
604
605
606
607
608
609
610
611
612
613
614
615
616
617
618
619
620
621
622
623
624
625
626
627
628
629
630
631
632
633
634
635
636
637
638
639
640
641
642
643
644
645
646
647
648
649
650
651
652
653
654
655
656
657
658
659
660
661
662
663
664
665
666
667
668
669
670
671
672
673
674
675
676
677
678
679
680
681
682
683
684
685
686
687
688
689
690
691
692
693
694
695
696
697
698
699
700
701
702
703
704
705
706
707
708
709
710
711
712
713
714
715
716
717
718
719
720
721
722
723
724
725
726
727
728
729
730
731
732
733
734
735
736
737
738
739
740
741
742
743
744
745
746
747
748
749
750
751
752
753
754
755
756
757
758
759
760
761
762
763
764
765
766
767
768
769
770
771
772
773
774
775
776
777
778
779
780
781
782
783
784
785
786
787
788
789
790
791
792
793
794
795
796
797
798
799
800
801
802
803
804
805
806
807
808
809
810
811
812
813
814
815
816
817
818
819
820
821
822
823
824
825
826
827
828
829
830
831
832
833
834
835
836
837
838
839
840
841
842
843
844
845
846
847
848
849
850
851
852
853
854
855
856
857
858
859
860
861
862
863
864
865
866
867
868
869
870
871
872
873
874
875
876
877
878
879
880
881
882
883
884
885
886
887
888
889
890
891
892
893
894
895
896
897
898
899
900
901
902
903
904
905
906
907
908
909
910
911
912
913
914
915
916
917
918
919
920
921
922
923
924
925
926
927
928
929
930
931
932
933
934
935
936
937
938
939
940
941
942
943
944
945
946
947
948
949
950
951
952
953
954
955
956
957
958
959
960
961
962
963
964
965
966
967
968
969
970
971
972
973
974
975
976
977
978
979
980
981
982
983
984
985
986
987
988
989
990
991
992
993
994
995
996
997
998
999
1000
1001
1002
1003
1004
1005
1006
1007
1008
1009
1010
1011
1012
1013
1014
1015
1016
1017
1018
1019
1020
1021
1022
1023
1024
1025
1026
1027
1028
1029
1030
1031
1032
1033
1034
1035
1036
1037
1038
1039
1040
1041
1042
1043
1044
1045
1046
1047
1048
1049
1050
1051
1052
1053
1054
1055
1056
1057
1058
1059
1060
1061
1062
1063
1064
1065
1066
1067
1068
1069
1070
1071
1072
1073
1074
1075
1076
1077
1078
1079
1080
1081
1082
1083
1084
1085
1086
1087
1088
1089
1090
1091
1092
1093
1094
1095
1096
1097
1098
1099
1100
1101
1102
1103
1104
1105
1106
1107
1108
1109
1110
1111
1112
1113
1114
1115
1116
1117
1118
1119
1120
1121
1122
1123
1124
1125
1126
1127
1128
1129
1130
1131
1132
1133
1134
1135
1136
1137
1138
1139
1140
1141
1142
1143
1144
1145
1146
1147
1148
1149
1150
1151
1152
1153
1154
1155
1156
1157
1158
1159
1160
1161
1162
1163
1164
1165
1166
1167
1168
1169
1170
1171
1172
1173
1174
1175
1176
1177
1178
1179
1180
1181
1182
1183
1184
1185
1186
1187
1188
1189
1190
1191
1192
|
%%
%% %CopyrightBegin%
%%
%% 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
%% compliance with the License. You should have received a copy of the
%% Erlang Public License along with this software. If not, it can be
%% retrieved online at http://www.erlang.org/.
%%
%% Software distributed under the License is distributed on an "AS IS"
%% basis, WITHOUT WARRANTY OF ANY KIND, either express or implied. See
%% the License for the specific language governing rights and limitations
%% under the License.
%%
%% %CopyrightEnd%
%%
%%
%% This module implements (as a process) the RFC 3588/6733 Peer State
%% Machine modulo the necessity of adapting the peer election to the
%% fact that we don't know the identity of a peer until we've received
%% a CER/CEA from it.
%%
-module(diameter_peer_fsm).
-behaviour(gen_server).
%% Interface towards diameter_watchdog.
-export([start/3,
result_code/2]).
%% gen_server callbacks
-export([init/1,
handle_call/3,
handle_cast/2,
handle_info/2,
terminate/2,
code_change/3]).
%% diameter_peer_fsm_sup callback
-export([start_link/1]).
%% internal callbacks
-export([match/1]).
-include_lib("diameter/include/diameter.hrl").
-include("diameter_internal.hrl").
%% Values of Disconnect-Cause in DPR.
-define(GOAWAY, 2). %% DO_NOT_WANT_TO_TALK_TO_YOU
-define(BUSY, 1). %% BUSY
-define(REBOOT, 0). %% REBOOTING
%% Values of Inband-Security-Id.
-define(NO_INBAND_SECURITY, 0).
-define(TLS, 1).
%% Note that the a common dictionary hrl is purposely not included
%% since the common dictionary is an argument to start/3.
%% Keys in process dictionary.
-define(CB_KEY, cb). %% capabilities callback
-define(DPR_KEY, dpr). %% disconnect callback
-define(REF_KEY, ref). %% transport_ref()
-define(Q_KEY, q). %% transport start queue
-define(START_KEY, start). %% start of connected transport
-define(SEQUENCE_KEY, mask). %% mask for sequence numbers
-define(RESTRICT_KEY, restrict). %% nodes for connection check
%% The default sequence mask.
-define(NOMASK, {0,32}).
%% A 2xxx series Result-Code. Not necessarily 2001.
-define(IS_SUCCESS(N), 2 == (N) div 1000).
%% Guards.
-define(IS_UINT32(N), (is_integer(N) andalso 0 =< N andalso 0 == N bsr 32)).
-define(IS_TIMEOUT(N), ?IS_UINT32(N)).
-define(IS_CAUSE(N), N == ?REBOOT; N == rebooting;
N == ?GOAWAY; N == goaway;
N == ?BUSY; N == busy).
%% RFC 3588:
%%
%% Timeout An application-defined timer has expired while waiting
%% for some event.
%%
-define(EVENT_TIMEOUT, 10000).
%% Default timeout for reception of CER/CEA.
%% Default timeout for DPA in response to DPR. A bit short but the
%% timeout used to be hardcoded. (So it could be worse.)
-define(DPA_TIMEOUT, 1000).
-type uint32() :: diameter:'Unsigned32'().
-record(state,
{state %% of RFC 3588 Peer State Machine
:: {'Wait-Conn-Ack', uint32()}
| recv_CER
| {'Wait-CEA', uint32(), uint32()}
| 'Open',
mode :: accept | connect | {connect, reference()},
parent :: pid(), %% watchdog process
transport :: pid(), %% transport process
dictionary :: module(), %% common dictionary
service :: #diameter_service{},
dpr = false :: false | {uint32(), uint32()},
%% | hop by hop and end to end identifiers
length_errors :: exit | handle | discard}).
%% There are non-3588 states possible as a consequence of 5.6.1 of the
%% standard and the corresponding problem for incoming CEA's: we don't
%% know who we're talking to until either a CER or CEA has been
%% received. The CEA problem in particular makes it impossible to
%% follow the state machine exactly as documented in 3588: there can
%% be no election until the CEA arrives and we have an Origin-Host to
%% elect.
%%
%% Once upon a time start/2 started a process akin to that started by
%% start/3 below, which in turn started a watchdog/transport process
%% with the result that the watchdog could send DWR/DWA regardless of
%% whether or not the corresponding Peer State Machine was in its open
%% state; that is, before capabilities exchange had taken place. This
%% is not what RFC's 3588 and 3539 say (albeit not very clearly).
%% Watchdog messages are only exchanged on *open* connections, so the
%% 3539 state machine is more naturally placed on top of the 3588 Peer
%% State Machine rather than closer to the transport. This is what we
%% now do below: connect/accept call diameter_watchdog and return the
%% pid of the watchdog process, and the watchdog in turn calls start/3
%% below to start the process implementing the Peer State Machine.
%%
%% ---------------------------------------------------------------------------
%% # start/3
%% ---------------------------------------------------------------------------
-spec start(T, [Opt], {diameter:sequence(),
[node()],
module(),
#diameter_service{}})
-> {reference(), pid()}
when T :: {connect|accept, diameter:transport_ref()},
Opt :: diameter:transport_opt().
%% diameter_config requires a non-empty list of applications on the
%% service but diameter_service then constrains the list to any
%% specified on the transport in question. Check here that the list is
%% still non-empty.
start({_,_} = Type, Opts, S) ->
Ack = make_ref(),
T = {Ack, self(), Type, Opts, S},
{ok, Pid} = diameter_peer_fsm_sup:start_child(T),
try
{erlang:monitor(process, Pid), Pid}
after
Pid ! Ack
end.
start_link(T) ->
{ok, _} = proc_lib:start_link(?MODULE,
init,
[T],
infinity,
diameter_lib:spawn_opts(server, [])).
%% ---------------------------------------------------------------------------
%% ---------------------------------------------------------------------------
%% init/1
init(T) ->
proc_lib:init_ack({ok, self()}),
gen_server:enter_loop(?MODULE, [], i(T)).
i({Ack, WPid, {M, Ref} = T, Opts, {Mask, Nodes, Dict0, Svc}}) ->
erlang:monitor(process, WPid),
wait(Ack, WPid),
diameter_stats:reg(Ref),
{[Cs,Ds], Rest} = proplists:split(Opts, [capabilities_cb, disconnect_cb]),
putr(?CB_KEY, {Ref, [F || {_,F} <- Cs]}),
putr(?DPR_KEY, [F || {_, F} <- Ds]),
putr(?REF_KEY, Ref),
putr(?SEQUENCE_KEY, Mask),
putr(?RESTRICT_KEY, Nodes),
Tmo = proplists:get_value(capx_timeout, Opts, ?EVENT_TIMEOUT),
OnLengthErr = proplists:get_value(length_errors, Opts, exit),
{TPid, Addrs} = start_transport(T, Rest, Svc),
#state{state = {'Wait-Conn-Ack', Tmo},
parent = WPid,
transport = TPid,
dictionary = Dict0,
mode = M,
service = svc(Svc, Addrs),
length_errors = OnLengthErr}.
%% The transport returns its local ip addresses so that different
%% transports on the same service can use different local addresses.
%% The local addresses are put into Host-IP-Address avps here when
%% sending capabilities exchange messages.
%% Wait for the caller to have a monitor to avoid a race with our
%% death. (Since the exit reason is used in diameter_service.)
wait(Ref, Pid) ->
receive
Ref ->
ok;
{'DOWN', _, process, Pid, _} = D ->
exit({shutdown, D})
end.
start_transport(T, Opts, #diameter_service{capabilities = LCaps} = Svc) ->
Addrs0 = LCaps#diameter_caps.host_ip_address,
start_transport(Addrs0, {T, Opts, Svc}).
start_transport(Addrs0, T) ->
case diameter_peer:start(T) of
{TPid, Addrs, Tmo, Data} ->
erlang:monitor(process, TPid),
q_next(TPid, Addrs0, Tmo, Data),
{TPid, Addrs};
{error, No} ->
exit({shutdown, {no_connection, No}})
end.
svc(#diameter_service{capabilities = LCaps0} = Svc, Addrs) ->
#diameter_caps{host_ip_address = Addrs0}
= LCaps0,
case Addrs0 of
[] ->
LCaps = LCaps0#diameter_caps{host_ip_address = Addrs},
Svc#diameter_service{capabilities = LCaps};
[_|_] ->
Svc
end.
readdr(#diameter_service{capabilities = LCaps0} = Svc, Addrs) ->
LCaps = LCaps0#diameter_caps{host_ip_address = Addrs},
Svc#diameter_service{capabilities = LCaps}.
%% The 4-tuple Data returned from diameter_peer:start/1 identifies the
%% transport module/config use to start the transport process in
%% question as well as any alternates to try if a connection isn't
%% established within Tmo.
q_next(TPid, Addrs0, Tmo, {_,_,_,_} = Data) ->
send_after(Tmo, {connection_timeout, TPid}),
putr(?Q_KEY, {Addrs0, Tmo, Data}).
%% Connection has been established: retain the started
%% pid/module/config in the process dictionary. This is a part of the
%% interface defined by this module, so that the transport pid can be
%% found when constructing service_info (in order to extract further
%% information from it).
keep_transport(TPid) ->
{_, _, {{_,_,_} = T, _, _, _}} = eraser(?Q_KEY),
putr(?START_KEY, {TPid, T}).
send_after(infinity, _) ->
ok;
send_after(Tmo, T) ->
erlang:send_after(Tmo, self(), T).
%% handle_call/3
handle_call(_, _, State) ->
{reply, nok, State}.
%% handle_cast/2
handle_cast(_, State) ->
{noreply, State}.
%% handle_info/1
handle_info(T, #state{} = State) ->
try transition(T, State) of
ok ->
{noreply, State};
#state{state = X} = S ->
?LOGC(X /= State#state.state, transition, X),
{noreply, S};
{stop, Reason} ->
?LOG(stop, Reason),
{stop, {shutdown, Reason}, State};
stop ->
?LOG(stop, T),
{stop, {shutdown, T}, State}
catch
exit: {diameter_codec, encode, T} = Reason ->
incr_error(send, T, State#state.dictionary),
?LOG(stop, Reason),
{stop, {shutdown, Reason}, State};
{?MODULE, Tag, Reason} ->
?LOG(stop, Tag),
{stop, {shutdown, Reason}, State}
end.
%% The form of the throw caught here is historical. It's
%% significant that it's not a 2-tuple, as in ?FAILURE(Reason),
%% since these are caught elsewhere.
%% Note that there's no guarantee that the service and transport
%% capabilities are good enough to build a CER/CEA that can be
%% succesfully encoded. It's not checked at diameter:add_transport/2
%% since this can be called before creating the service.
%% terminate/2
terminate(_, _) ->
ok.
%% code_change/3
code_change(_, State, _) ->
{ok, State}.
%% ---------------------------------------------------------------------------
%% ---------------------------------------------------------------------------
putr(Key, Val) ->
put({?MODULE, Key}, Val).
getr(Key) ->
get({?MODULE, Key}).
eraser(Key) ->
erase({?MODULE, Key}).
%% transition/2
%% Connection to peer.
transition({diameter, {TPid, connected, Remote}},
#state{transport = TPid,
state = PS,
mode = M}
= S) ->
{'Wait-Conn-Ack', _} = PS, %% assert
connect = M, %%
keep_transport(TPid),
send_CER(S#state{mode = {M, Remote}});
transition({diameter, {TPid, connected, Remote, LAddrs}},
#state{transport = TPid,
service = Svc}
= S) ->
transition({diameter, {TPid, connected, Remote}},
S#state{service = svc(Svc, LAddrs)});
%% Connection from peer.
transition({diameter, {TPid, connected}},
#state{transport = TPid,
state = PS,
mode = M,
parent = Pid}
= S) ->
{'Wait-Conn-Ack', Tmo} = PS, %% assert
accept = M, %%
keep_transport(TPid),
Pid ! {accepted, self()},
start_timer(Tmo, S#state{state = recv_CER});
%% Connection established after receiving a connection_timeout
%% message. This may be followed by an incoming message which arrived
%% before the transport was killed and this can't be distinguished
%% from one from the transport that's been started to replace it.
transition({diameter, T}, _)
when tuple_size(T) < 5, connected == element(2,T) ->
{stop, connection_timeout};
%% Connection has timed out: start an alternate.
transition({connection_timeout = T, TPid},
#state{transport = TPid,
state = {'Wait-Conn-Ack', _}}
= S) ->
exit(TPid, {shutdown, T}),
start_next(S);
%% Connect timeout after connection or alternate start: ignore.
transition({connection_timeout, _}, _) ->
ok;
%% Incoming message from the transport.
transition({diameter, {recv, Pkt}}, S) ->
recv(Pkt, S);
%% Timeout when still in the same state ...
transition({timeout = T, PS}, #state{state = PS}) ->
{stop, {capx(PS), T}};
%% ... or not.
transition({timeout, _}, _) ->
ok;
%% Outgoing message.
transition({send, Msg}, S) ->
outgoing(Msg, S),
ok;
%% Request for graceful shutdown at remove_transport, stop_service of
%% application shutdown.
transition({shutdown, Pid, Reason}, #state{parent = Pid, dpr = false} = S) ->
dpr(Reason, S);
transition({shutdown, Pid, _}, #state{parent = Pid}) ->
ok;
%% DPA reception has timed out.
transition(dpa_timeout, _) ->
stop;
%% Someone wants to know a resolved port: forward to the transport process.
transition({resolve_port, _Pid} = T, #state{transport = TPid}) ->
TPid ! T,
ok;
%% Parent has died.
transition({'DOWN', _, process, WPid, _},
#state{parent = WPid}) ->
stop;
%% Transport has died before connection timeout.
transition({'DOWN', _, process, TPid, _},
#state{transport = TPid}
= S) ->
start_next(S);
%% Transport has died after connection timeout.
transition({'DOWN', _, process, _, _}, _) ->
ok;
%% State query.
transition({state, Pid}, #state{state = S, transport = TPid}) ->
Pid ! {self(), [S, TPid]},
ok.
%% Crash on anything unexpected.
capx(recv_CER) ->
'CER';
capx({'Wait-CEA', _, _}) ->
'CEA'.
%% start_next/1
start_next(#state{service = Svc0} = S) ->
case getr(?Q_KEY) of
{Addrs0, Tmo, Data} ->
Svc = readdr(Svc0, Addrs0),
{TPid, Addrs} = start_transport(Addrs0, {Svc, Tmo, Data}),
S#state{transport = TPid,
service = svc(Svc, Addrs)};
undefined ->
stop
end.
%% send_CER/1
send_CER(#state{state = {'Wait-Conn-Ack', Tmo},
mode = {connect, Remote},
service = #diameter_service{capabilities = LCaps},
transport = TPid,
dictionary = Dict}
= S) ->
OH = LCaps#diameter_caps.origin_host,
req_send_CER(OH, Remote)
orelse
close({already_connected, Remote, LCaps}),
CER = build_CER(S),
#diameter_packet{header = #diameter_header{end_to_end_id = Eid,
hop_by_hop_id = Hid}}
= Pkt
= encode(CER, Dict),
incr(send, Pkt, Dict),
send(TPid, Pkt),
?LOG(send, 'CER'),
start_timer(Tmo, S#state{state = {'Wait-CEA', Hid, Eid}}).
%% Register ourselves as connecting to the remote endpoint in
%% question. This isn't strictly necessary since a peer implementing
%% the 3588 Peer State Machine should reject duplicate connection's
%% from the same peer but there's little point in us setting up a
%% duplicate connection in the first place. This could also include
%% the transport protocol being used but since we're blind to
%% transport just avoid duplicate connections to the same host/port.
req_send_CER(OriginHost, Remote) ->
register_everywhere({?MODULE, connection, OriginHost, {remote, Remote}}).
%% start_timer/2
start_timer(Tmo, #state{state = PS} = S) ->
erlang:send_after(Tmo, self(), {timeout, PS}),
S.
%% build_CER/1
build_CER(#state{service = #diameter_service{capabilities = LCaps},
dictionary = Dict}) ->
{ok, CER} = diameter_capx:build_CER(LCaps, Dict),
CER.
%% encode/2
encode(Rec, Dict) ->
Seq = diameter_session:sequence({_,_} = getr(?SEQUENCE_KEY)),
Hdr = #diameter_header{version = ?DIAMETER_VERSION,
end_to_end_id = Seq,
hop_by_hop_id = Seq},
diameter_codec:encode(Dict, #diameter_packet{header = Hdr,
msg = Rec}).
%% recv/2
recv(#diameter_packet{header = #diameter_header{} = Hdr}
= Pkt,
#state{parent = Pid,
dictionary = Dict0}
= S) ->
Name = diameter_codec:msg_name(Dict0, Hdr),
Pid ! {recv, self(), Name, Pkt},
rcv(Name, Pkt, S);
recv(#diameter_packet{header = undefined,
bin = Bin}
= Pkt,
S) ->
recv(diameter_codec:decode_header(Bin), Pkt, S);
recv(Bin, S) ->
recv(#diameter_packet{bin = Bin}, S).
%% recv/3
recv(#diameter_header{length = Len}
= H,
#diameter_packet{bin = Bin}
= Pkt,
#state{length_errors = E}
= S)
when E == handle;
0 == Len rem 4, bit_size(Bin) == 8*Len ->
recv(Pkt#diameter_packet{header = H}, S);
recv(#diameter_header{}
= H,
#diameter_packet{bin = Bin},
#state{length_errors = E}) ->
T = {size(Bin), bit_size(Bin) rem 8, H},
invalid(E, message_length_mismatch, T);
recv(false, #diameter_packet{bin = Bin}, #state{length_errors = E}) ->
invalid(E, truncated_header, Bin).
%% Note that counters here only count discarded messages.
invalid(E, Reason, T) ->
diameter_stats:incr(Reason),
E == exit andalso close({Reason, T}),
?LOG(Reason, T),
ok.
%% rcv/3
%% Incoming CEA.
rcv('CEA' = N,
#diameter_packet{header = #diameter_header{end_to_end_id = Eid,
hop_by_hop_id = Hid}}
= Pkt,
#state{state = {'Wait-CEA', Hid, Eid}}
= S) ->
?LOG(recv, N),
handle_CEA(Pkt, S);
%% Incoming CER
rcv('CER' = N, Pkt, #state{state = recv_CER} = S) ->
handle_request(N, Pkt, S);
%% Anything but CER/CEA in a non-Open state is an error, as is
%% CER/CEA in anything but recv_CER/Wait-CEA.
rcv(Name, _, #state{state = PS})
when PS /= 'Open';
Name == 'CER';
Name == 'CEA' ->
{stop, {Name, PS}};
rcv('DPR' = N, Pkt, S) ->
handle_request(N, Pkt, S);
%% DPA in response to DPR and with the expected identifiers.
rcv('DPA' = N,
#diameter_packet{header = #diameter_header{end_to_end_id = Eid,
hop_by_hop_id = Hid}
= H}
= Pkt,
#state{dictionary = Dict0,
transport = TPid,
dpr = {Hid, Eid}}) ->
?LOG(recv, N),
incr(recv, H, Dict0),
incr_rc(recv, diameter_codec:decode(Dict0, Pkt), Dict0),
diameter_peer:close(TPid),
{stop, N};
%% Ignore anything else, an unsolicited DPA in particular.
rcv(N, #diameter_packet{header = H}, _)
when N == 'CER';
N == 'CEA';
N == 'DPR';
N == 'DPA' ->
?LOG(ignored, N),
%% Note that these aren't counted in the normal recv counter.
diameter_stats:incr({diameter_codec:msg_id(H), recv, ignored}),
ok;
rcv(_, _, _) ->
ok.
%% incr/3
incr(Dir, Hdr, Dict0) ->
diameter_traffic:incr(Dir, Hdr, self(), Dict0).
%% incr_rc/3
incr_rc(Dir, Pkt, Dict0) ->
diameter_traffic:incr_rc(Dir, Pkt, self(), Dict0).
%% incr_error/3
incr_error(Dir, Pkt, Dict0) ->
diameter_traffic:incr_error(Dir, Pkt, self(), Dict0).
%% send/2
%% Msg here could be a #diameter_packet or a binary depending on who's
%% sending. In particular, the watchdog will send DWR as a binary
%% while messages coming from clients will be in a #diameter_packet.
send(Pid, Msg) ->
diameter_peer:send(Pid, Msg).
%% outgoing/2
%% DPR not sent: send.
outgoing(Msg, #state{transport = TPid, dpr = false}) ->
send(TPid, Msg);
%% Outgoing answer: send.
outgoing(#diameter_packet{header = #diameter_header{is_request = false}}
= Pkt,
#state{transport = TPid}) ->
send(TPid, Pkt);
%% Outgoing request: discard.
outgoing(Msg, #state{dpr = {_,_}}) ->
invalid(false, send_after_dpr, header(Msg)).
header(#diameter_packet{header = H}) ->
H;
header(Bin) -> %% DWR
diameter_codec:decode_header(Bin).
%% handle_request/3
%%
%% Incoming CER or DPR.
handle_request(Name,
#diameter_packet{header = H} = Pkt,
#state{dictionary = Dict0} = S) ->
?LOG(recv, Name),
incr(recv, H, Dict0),
send_answer(Name, diameter_codec:decode(Dict0, Pkt), S).
%% send_answer/3
send_answer(Type, ReqPkt, #state{transport = TPid, dictionary = Dict} = S) ->
incr_error(recv, ReqPkt, Dict),
#diameter_packet{header = H,
transport_data = TD}
= ReqPkt,
{Msg, PostF} = build_answer(Type, ReqPkt, S),
%% An answer message clears the R and T flags and retains the P
%% flag. The E flag is set at encode.
Pkt = #diameter_packet{header
= H#diameter_header{version = ?DIAMETER_VERSION,
is_request = false,
is_error = undefined,
is_retransmitted = false},
msg = Msg,
transport_data = TD},
AnsPkt = diameter_codec:encode(Dict, Pkt),
incr(send, AnsPkt, Dict),
incr_rc(send, AnsPkt, Dict),
send(TPid, AnsPkt),
?LOG(send, ans(Type)),
eval(PostF, S).
ans('CER') -> 'CEA';
ans('DPR') -> 'DPA'.
eval([F|A], S) ->
apply(F, A ++ [S]);
eval(T, _) ->
close(T).
%% build_answer/3
build_answer('CER',
#diameter_packet{msg = CER,
header = #diameter_header{version
= ?DIAMETER_VERSION,
is_error = false},
errors = []}
= Pkt,
#state{dictionary = Dict0}
= S) ->
{SupportedApps, RCaps, CEA} = recv_CER(CER, S),
[RC, IS] = Dict0:'#get-'(['Result-Code', 'Inband-Security-Id'], CEA),
#diameter_caps{origin_host = {OH, DH}}
= Caps
= capz(caps(S), RCaps),
try
2001 == RC %% DIAMETER_SUCCESS
orelse ?THROW(RC),
register_everywhere({?MODULE, connection, OH, DH})
orelse ?THROW(4003), %% DIAMETER_ELECTION_LOST
caps_cb(Caps)
of
N -> {cea(CEA, N, Dict0), [fun open/5, Pkt,
SupportedApps,
Caps,
{accept, inband_security(IS)}]}
catch
?FAILURE(Reason) ->
rejected(Reason, {'CER', Reason, Caps, Pkt}, S)
end;
%% The error checks below are similar to those in diameter_traffic for
%% other messages. Should factor out the commonality.
build_answer(Type,
#diameter_packet{header = H,
errors = Es}
= Pkt,
S) ->
{RC, FailedAVP} = result_code(H, Es),
{answer(Type, RC, FailedAVP, S), post(Type, RC, Pkt, S)}.
inband_security([]) ->
?NO_INBAND_SECURITY;
inband_security([IS]) ->
IS.
cea(CEA, ok, _) ->
CEA;
cea(CEA, 2001, _) ->
CEA;
cea(CEA, RC, Dict0) ->
Dict0:'#set-'({'Result-Code', RC}, CEA).
post('CER' = T, RC, Pkt, S) ->
{T, caps(S), {RC, Pkt}};
post('DPR' = T, _, _, #state{parent = Pid}) ->
[fun(S) -> Pid ! {T, self()}, S end].
rejected({capabilities_cb, _F, Reason}, T, S) ->
rejected(Reason, T, S);
rejected(discard, T, _) ->
close(T);
rejected({N, Es}, T, S) ->
{answer('CER', N, failed_avp(N, Es), S), T};
rejected(N, T, S) ->
{answer('CER', N, [], S), T}.
failed_avp(RC, [{RC, Avp} | _]) ->
[{'Failed-AVP', [[{'AVP', [Avp]}]]}];
failed_avp(RC, [_ | Es]) ->
failed_avp(RC, Es);
failed_avp(_, [] = No) ->
No.
answer(Type, RC, FailedAVP, S) ->
set(answer(Type, RC, S), FailedAVP).
answer(Type, RC, S) ->
answer_message(answer(Type, S), RC).
%% answer_message/2
answer_message([_ | Avps], RC)
when 3000 =< RC, RC < 4000 ->
['answer-message', {'Result-Code', RC}
| lists:filter(fun is_origin/1, Avps)];
answer_message(Msg, RC) ->
Msg ++ [{'Result-Code', RC}].
is_origin({N, _}) ->
N == 'Origin-Host'
orelse N == 'Origin-Realm'
orelse N == 'Origin-State-Id'.
%% set/2
set(Ans, []) ->
Ans;
set(['answer-message' | _] = Ans, FailedAvp) ->
Ans ++ [{'AVP', [FailedAvp]}];
set([_|_] = Ans, FailedAvp) ->
Ans ++ FailedAvp.
%% result_code/2
result_code(#diameter_header{is_error = true}, _) ->
{3008, []}; %% DIAMETER_INVALID_HDR_BITS
result_code(#diameter_header{version = ?DIAMETER_VERSION}, Es) ->
rc(Es);
result_code(_, _) ->
{5011, []}. %% DIAMETER_UNSUPPORTED_VERSION
%% rc/1
rc([]) ->
{2001, []}; %% DIAMETER_SUCCESS
rc([{RC, _} | _] = Es) ->
{RC, failed_avp(RC, Es)};
rc([RC|_]) ->
{RC, []}.
%% DIAMETER_INVALID_HDR_BITS 3008
%% A request was received whose bits in the Diameter header were
%% either set to an invalid combination, or to a value that is
%% inconsistent with the command code's definition.
%% DIAMETER_INVALID_AVP_BITS 3009
%% A request was received that included an AVP whose flag bits are
%% set to an unrecognized value, or that is inconsistent with the
%% AVP's definition.
%% ELECTION_LOST 4003
%% The peer has determined that it has lost the election process and
%% has therefore disconnected the transport connection.
%% DIAMETER_NO_COMMON_APPLICATION 5010
%% This error is returned when a CER message is received, and there
%% are no common applications supported between the peers.
%% DIAMETER_UNSUPPORTED_VERSION 5011
%% This error is returned when a request was received, whose version
%% number is unsupported.
%% answer/2
answer(Name, #state{service = #diameter_service{capabilities = Caps}}) ->
a(Name, Caps).
a('CER', #diameter_caps{vendor_id = Vid,
origin_host = Host,
origin_realm = Realm,
host_ip_address = Addrs,
product_name = Name,
origin_state_id = OSI}) ->
['CEA', {'Origin-Host', Host},
{'Origin-Realm', Realm},
{'Host-IP-Address', Addrs},
{'Vendor-Id', Vid},
{'Product-Name', Name},
{'Origin-State-Id', OSI}];
a('DPR', #diameter_caps{origin_host = {Host, _},
origin_realm = {Realm, _}}) ->
['DPA', {'Origin-Host', Host},
{'Origin-Realm', Realm}].
%% recv_CER/2
recv_CER(CER, #state{service = Svc, dictionary = Dict}) ->
case diameter_capx:recv_CER(CER, Svc, Dict) of
{ok, T} ->
T;
{error, Reason} ->
close({'CER', CER, Svc, Dict, Reason})
end.
%% handle_CEA/2
handle_CEA(#diameter_packet{header = H}
= Pkt,
#state{dictionary = Dict0,
service = #diameter_service{capabilities = LCaps}}
= S) ->
incr(recv, H, Dict0),
#diameter_packet{}
= DPkt
= diameter_codec:decode(Dict0, Pkt),
RC = result_code(incr_rc(recv, DPkt, Dict0)),
{SApps, IS, RCaps} = recv_CEA(DPkt, S),
#diameter_caps{origin_host = {OH, DH}}
= Caps
= capz(LCaps, RCaps),
%% Ensure that we don't already have a connection to the peer in
%% question. This isn't the peer election of 3588 except in the
%% sense that, since we don't know who we're talking to until we
%% receive a CER/CEA, the first that arrives wins the right to a
%% connection with the peer.
try
is_integer(RC) andalso ?IS_SUCCESS(RC)
orelse ?THROW(RC),
[] == SApps
andalso ?THROW(no_common_application),
[] == IS
andalso ?THROW(no_common_security),
register_everywhere({?MODULE, connection, OH, DH})
orelse ?THROW(election_lost),
caps_cb(Caps)
of
_ -> open(DPkt, SApps, Caps, {connect, hd([_] = IS)}, S)
catch
?FAILURE(Reason) -> close({'CEA', Reason, Caps, DPkt})
end.
%% Check more than the result code since the peer could send success
%% regardless. If not 2001 then a peer_up callback could do anything
%% required. It's not unimaginable that a peer agreeing to TLS after
%% capabilities exchange could send DIAMETER_LIMITED_SUCCESS = 2002,
%% even if this isn't required by RFC 3588.
result_code({'Result-Code', N}) ->
N;
result_code(_) ->
undefined.
%% recv_CEA/2
recv_CEA(#diameter_packet{header = #diameter_header{version
= ?DIAMETER_VERSION,
is_error = false},
msg = CEA,
errors = []},
#state{service = Svc,
dictionary = Dict}) ->
case diameter_capx:recv_CEA(CEA, Svc, Dict) of
{ok, T} ->
T;
{error, Reason} ->
close({'CEA', CEA, Svc, Dict, Reason})
end;
recv_CEA(Pkt, S) ->
close({'CEA', caps(S), Pkt}).
caps(#diameter_service{capabilities = Caps}) ->
Caps;
caps(#state{service = Svc}) ->
caps(Svc).
%% caps_cb/1
caps_cb(Caps) ->
{Ref, Ts} = eraser(?CB_KEY),
caps_cb(Ts, [Ref, Caps]).
caps_cb([], _) ->
ok;
caps_cb([F | Rest], T) ->
case diameter_lib:eval([F|T]) of
ok ->
caps_cb(Rest, T);
N when ?IS_SUCCESS(N) -> %% 2xxx result code: accept immediately
N;
Res ->
?THROW({capabilities_cb, F, rejected(Res)})
end.
%% Note that returning 2xxx causes the capabilities exchange to be
%% accepted directly, without further callbacks.
rejected(discard = T) ->
T;
rejected(unknown) ->
3010; %% DIAMETER_UNKNOWN_PEER
rejected(N)
when is_integer(N) ->
N.
%% open/5
open(Pkt, SupportedApps, Caps, {Type, IS}, #state{parent = Pid,
service = Svc}
= S) ->
#diameter_caps{origin_host = {_,_} = H,
inband_security_id = {LS,_}}
= Caps,
tls_ack(lists:member(?TLS, LS), Caps, Type, IS, S),
Pid ! {open, self(), H, {Caps, SupportedApps, Pkt}},
%% Replace capabilities record with local/remote pairs.
S#state{state = 'Open',
service = Svc#diameter_service{capabilities = Caps}}.
%% We've advertised TLS support: tell the transport the result
%% and expect a reply when the handshake is complete.
tls_ack(true, Caps, Type, IS, #state{transport = TPid}) ->
Ref = make_ref(),
TPid ! {diameter, {tls, Ref, Type, IS == ?TLS}},
receive
{diameter, {tls, Ref}} ->
ok;
{'DOWN', _, process, TPid, Reason} ->
close({tls_ack, Reason, Caps})
end;
%% Or not. Don't send anything to the transport so that transports
%% not supporting TLS work as before without modification.
tls_ack(false, _, _, _, _) ->
ok.
capz(#diameter_caps{} = L, #diameter_caps{} = R) ->
#diameter_caps{}
= list_to_tuple([diameter_caps | lists:zip(tl(tuple_to_list(L)),
tl(tuple_to_list(R)))]).
%% close/1
%%
%% A good function to trace on in case of problems with capabilities
%% exchange.
close(Reason) ->
throw({?MODULE, close, Reason}).
%% dpr/2
%%
%% The RFC isn't clear on whether DPR should be send in a non-Open
%% state. The Peer State Machine transitions it documents aren't
%% exhaustive (no Stop in Wait-I-CEA for example) so assume it's up to
%% the implementation and transition to Closed (ie. die) if we haven't
%% yet reached Open.
%% Connection is open, DPR has not been sent.
dpr(Reason, #state{state = 'Open',
dpr = false,
service = #diameter_service{capabilities = Caps}}
= S) ->
CBs = getr(?DPR_KEY),
Ref = getr(?REF_KEY),
Peer = {self(), Caps},
dpr(CBs, [Reason, Ref, Peer], S);
%% Connection is open, DPR already sent.
dpr(_, #state{state = 'Open'}) ->
ok;
%% Connection not open.
dpr(_Reason, _S) ->
stop.
%% dpr/3
%%
%% Note that an implementation that wants to do something
%% transport_module-specific can lookup the pid of the transport
%% process and contact it. (eg. diameter:service_info/2)
dpr([CB|Rest], [Reason | _] = Args, S) ->
case diameter_lib:eval([CB | Args]) of
{dpr, Opts} when is_list(Opts) ->
send_dpr(Reason, Opts, S);
dpr ->
send_dpr(Reason, [], S);
close = T ->
{stop, {disconnect_cb, T}};
ignore ->
dpr(Rest, Args, S);
T ->
?ERROR({disconnect_cb, CB, Args, T})
end;
dpr([], [Reason | _], S) ->
send_dpr(Reason, [], S).
-record(opts, {cause, timeout = ?DPA_TIMEOUT}).
send_dpr(Reason, Opts, #state{transport = TPid,
dictionary = Dict,
service = #diameter_service{capabilities = Caps}}
= S) ->
#opts{cause = Cause, timeout = Tmo}
= lists:foldl(fun opt/2,
#opts{cause = case Reason of
transport -> ?GOAWAY;
_ -> ?REBOOT
end,
timeout = ?DPA_TIMEOUT},
Opts),
#diameter_caps{origin_host = {OH, _},
origin_realm = {OR, _}}
= Caps,
#diameter_packet{header = #diameter_header{end_to_end_id = Eid,
hop_by_hop_id = Hid}}
= Pkt
= encode(['DPR', {'Origin-Host', OH},
{'Origin-Realm', OR},
{'Disconnect-Cause', Cause}],
Dict),
incr(send, Pkt, Dict),
send(TPid, Pkt),
dpa_timer(Tmo),
?LOG(send, 'DPR'),
S#state{dpr = {Hid, Eid}}.
opt({timeout, Tmo}, Rec)
when ?IS_TIMEOUT(Tmo) ->
Rec#opts{timeout = Tmo};
opt({cause, Cause}, Rec)
when ?IS_CAUSE(Cause) ->
Rec#opts{cause = cause(Cause)};
opt(T, _) ->
?ERROR({invalid_option, T}).
cause(rebooting) -> ?REBOOT;
cause(goaway) -> ?GOAWAY;
cause(busy) -> ?BUSY;
cause(N)
when ?IS_CAUSE(N) ->
N;
cause(N) ->
?ERROR({invalid_cause, N}).
dpa_timer(Tmo) ->
erlang:send_after(Tmo, self(), dpa_timeout).
%% register_everywhere/1
%%
%% Register a term and ensure it's not registered elsewhere. Note that
%% two process that simultaneously register the same term may well
%% both fail to do so this isn't foolproof.
%%
%% Everywhere is no longer everywhere, it's where a
%% restrict_connections service_opt() specifies.
register_everywhere(T) ->
reg(getr(?RESTRICT_KEY), T).
reg(Nodes, T) ->
add(lists:member(node(), Nodes), T) andalso unregistered(Nodes, T).
add(true, T) ->
diameter_reg:add_new(T);
add(false, T) ->
diameter_reg:add(T).
%% unregistered
%%
%% Ensure that the term in question isn't registered on other nodes.
unregistered(Nodes, T) ->
{ResL, _} = rpc:multicall(Nodes, ?MODULE, match, [{node(), T}]),
lists:all(fun nomatch/1, ResL).
nomatch({badrpc, {'EXIT', {undef, _}}}) -> %% no diameter on remote node
true;
nomatch(L) ->
[] == L.
%% match/1
match({Node, _})
when Node == node() ->
[];
match({_, T}) ->
try
diameter_reg:match(T)
catch
_:_ -> []
end.
|