summaryrefslogtreecommitdiffstats
path: root/src/OSSupport/Network.cpp
blob: b916fd80423b1a9ce3411861f2aae79419b0424f (plain) (blame)
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
1193
1194
1195
1196
1197
1198
1199
1200
1201
1202
1203
1204
1205
1206
1207
1208
1209
1210
1211
1212
1213
1214
1215
1216
1217
1218
1219
1220
1221
1222
1223
1224
1225
1226
1227
1228
1229
1230
1231
1232
1233
1234
1235
1236
1237
1238
1239
1240
1241
1242
1243
1244
1245
1246
1247
1248
1249
1250
1251
1252
1253
1254

// Network.cpp

// Implements the classes used for the Network API

#include "Globals.h"
#include "Network.h"
#include <event2/event.h>
#include <event2/thread.h>
#include <event2/bufferevent.h>
#include <event2/dns.h>
#include <event2/listener.h>
#include <thread>
#include "Event.h"
#include "CriticalSection.h"





////////////////////////////////////////////////////////////////////////////////
// Class definitions:

/** Holds information about an in-progress Hostname-to-IP lookup. */
class cHostnameLookup
{
	/** The callbacks to call for resolved names / errors. */
	cNetwork::cResolveNameCallbacksPtr m_Callbacks;

	/** The hostname that was queried (needed for the callbacks). */
	AString m_Hostname;

	static void Callback(int a_ErrCode, struct evutil_addrinfo * a_Addr, void * a_Self);

public:
	cHostnameLookup(const AString & a_Hostname, cNetwork::cResolveNameCallbacksPtr a_Callbacks);
};
typedef SharedPtr<cHostnameLookup> cHostnameLookupPtr;
typedef std::vector<cHostnameLookupPtr> cHostnameLookupPtrs;





/** Holds information about an in-progress IP-to-Hostname lookup. */
class cIPLookup
{
	/** The callbacks to call for resolved names / errors. */
	cNetwork::cResolveNameCallbacksPtr m_Callbacks;

	/** The IP that was queried (needed for the callbacks). */
	AString m_IP;

	static void Callback(int a_Result, char a_Type, int a_Count, int a_Ttl, void * a_Addresses, void * a_Self);

public:
	cIPLookup(const AString & a_IP, cNetwork::cResolveNameCallbacksPtr a_Callbacks);
};
typedef SharedPtr<cIPLookup> cIPLookupPtr;
typedef std::vector<cIPLookupPtr> cIPLookupPtrs;





// fwd:
class cServerHandleImpl;





/** Implements the cTCPLink details so that it can represent the single connection between two endpoints. */
class cTCPLinkImpl:
	public cTCPLink
{
	typedef cTCPLink super;
	friend class cServerHandleImpl;

public:
	/** Creates a new link to be queued to connect to a specified host:port.
	Used for outgoing connections created using cNetwork::Connect().
	Call Connect() first, before using the link. */
	cTCPLinkImpl(const cCallbacksPtr a_LinkCallbacks);

	/** Creates a new link based on the given socket.
	Used for connections accepted in a server using cNetwork::Listen().
	a_Address and a_AddrLen describe the remote peer that has connected. */
	cTCPLinkImpl(evutil_socket_t a_Socket, cCallbacksPtr a_LinkCallbacks, cServerHandleImpl * a_Server, const sockaddr * a_Address, int a_AddrLen);

	/** Destroys the LibEvent handle representing the link. */
	~cTCPLinkImpl();

	/** Queues a connection request to the specified host.
	a_ConnectCallbacks must be valid.
	The object must have been constructed by the right constructor (without the Socket param). */
	bool Connect(const AString & a_Host, UInt16 a_Port, cNetwork::cConnectCallbacksPtr a_ConnectCallbacks);

	// cTCPLink overrides:
	virtual bool Send(const void * a_Data, size_t a_Length) override;
	virtual AString GetLocalIP(void) const override { return m_LocalIP; }
	virtual UInt16 GetLocalPort(void) const override { return m_LocalPort; }
	virtual AString GetRemoteIP(void) const override { return m_RemoteIP; }
	virtual UInt16 GetRemotePort(void) const override { return m_RemotePort; }
	virtual void Shutdown(void) override;
	virtual void Close(void) override;

protected:

	/** Callbacks to call when the connection is established.
	May be NULL if not used. Only used for outgoing connections (cNetwork::Connect()). */
	cNetwork::cConnectCallbacksPtr m_ConnectCallbacks;

	/** The LibEvent handle representing this connection. */
	bufferevent * m_BufferEvent;

	/** The server handle that has created this link.
	Only valid for incoming connections, NULL for outgoing connections. */
	cServerHandleImpl * m_Server;

	/** The IP address of the local endpoint. Valid only after the socket has been connected. */
	AString m_LocalIP;

	/** The port of the local endpoint. Valid only after the socket has been connected. */
	UInt16 m_LocalPort;

	/** The IP address of the remote endpoint. Valid only after the socket has been connected. */
	AString m_RemoteIP;

	/** The port of the remote endpoint. Valid only after the socket has been connected. */
	UInt16 m_RemotePort;


	/** Callback that LibEvent calls when there's data available from the remote peer. */
	static void ReadCallback(bufferevent * a_BufferEvent, void * a_Self);

	/** Callback that LibEvent calls when there's a non-data-related event on the socket. */
	static void EventCallback(bufferevent * a_BufferEvent, short a_What, void * a_Self);

	/** Sets a_IP and a_Port to values read from a_Address, based on the correct address family. */
	static void UpdateAddress(const sockaddr * a_Address, int a_AddrLen, AString & a_IP, UInt16 & a_Port);

	/** Updates m_LocalIP and m_LocalPort based on the metadata read from the socket. */
	void UpdateLocalAddress(void);

	/** Updates m_RemoteIP and m_RemotePort based on the metadata read from the socket. */
	void UpdateRemoteAddress(void);
};
typedef SharedPtr<cTCPLinkImpl> cTCPLinkImplPtr;
typedef std::vector<cTCPLinkImplPtr> cTCPLinkImplPtrs;





/** Implements the cServerHandle details so that it can represent a real server socket, with a list of clients. */
class cServerHandleImpl:
	public cServerHandle
{
	typedef cServerHandle super;
	friend class cTCPLinkImpl;

public:
	/** Creates a new instance with the specified callbacks.
	Initializes the internals, but doesn't start listening yet. */
	cServerHandleImpl(
		cNetwork::cListenCallbacksPtr a_ListenCallbacks,
		cTCPLink::cCallbacksPtr a_LinkCallbacks
	);

	/** Closes the server, dropping all the connections. */
	~cServerHandleImpl();

	/** Starts listening on the specified port.
	Both IPv4 and IPv6 interfaces are used, if possible. */
	bool Listen(UInt16 a_Port);

	// cServerHandle overrides:
	virtual void Close(void) override;
	virtual bool IsListening(void) const override { return m_IsListening; }

protected:
	/** The callbacks used to notify about incoming connections. */
	cNetwork::cListenCallbacksPtr m_ListenCallbacks;

	/** The callbacks used to create new cTCPLink instances for incoming connections. */
	cTCPLink::cCallbacksPtr m_LinkCallbacks;

	/** The LibEvent handle representing the main listening socket. */
	evconnlistener * m_ConnListener;

	/** The LibEvent handle representing the secondary listening socket (only when side-by-side listening is needed, such as WinXP). */
	evconnlistener * m_SecondaryConnListener;

	/** Set to true when the server is initialized successfully and is listening for incoming connections. */
	bool m_IsListening;

	/** Container for all currently active connections on this server. */
	cTCPLinkImplPtrs m_Connections;

	/** Mutex protecting m_Connections againt multithreaded access. */
	cCriticalSection m_CS;


	/** The callback called by LibEvent upon incoming connection. */
	static void Callback(evconnlistener * a_Listener, evutil_socket_t a_Socket, sockaddr * a_Addr, int a_Len, void * a_Self);

	/** Removes the specified link from m_Connections.
	Called by cTCPLinkImpl when the link is terminated. */
	void RemoveLink(const cTCPLinkImpl * a_Link);
};
typedef SharedPtr<cServerHandleImpl> cServerHandleImplPtr;
typedef std::vector<cServerHandleImplPtr> cServerHandleImplPtrs;





class cNetworkSingleton
{
	friend class cHostnameLookup;    // Needs access to m_DNSBase
	friend class cIPLookup;          // Needs access to m_DNSBase
	friend class cTCPLinkImpl;       // Needs access to m_EventBase and m_DNSBase
	friend class cServerHandleImpl;  // Needs access to m_EventBase

public:
	/** Returns the singleton instance of this class */
	static cNetworkSingleton & Get(void);


	// The following functions are implementations for the cNetwork class

	/** Queues a TCP connection to be made to the specified host.
	Calls one the connection callbacks (success, error) when the connection is successfully established, or upon failure.
	The a_LinkCallbacks is passed to the newly created cTCPLink.
	Returns true if queueing was successful, false on failure to queue.
	Note that the return value doesn't report the success of the actual connection; the connection is established asynchronously in the background. */
	bool Connect(
		const AString & a_Host,
		const UInt16 a_Port,
		cNetwork::cConnectCallbacksPtr a_ConnectCallbacks,
		cTCPLink::cCallbacksPtr a_LinkCallbacks
	);


	/** Opens up the specified port for incoming connections.
	Calls an OnAccepted callback for each incoming connection.
	A cTCPLink with the specified link callbacks is created for each connection.
	Returns a cServerHandle that can be used to query the operation status and close the server. */
	cServerHandlePtr Listen(
		const UInt16 a_Port,
		cNetwork::cListenCallbacksPtr a_ListenCallbacks,
		cTCPLink::cCallbacksPtr a_LinkCallbacks
	);


	/** Queues a DNS query to resolve the specified hostname to IP address.
	Calls one of the callbacks when the resolving succeeds, or when it fails.
	Returns true if queueing was successful, false if not.
	Note that the return value doesn't report the success of the actual lookup; the lookup happens asynchronously on the background. */
	bool HostnameToIP(
		const AString & a_Hostname,
		cNetwork::cResolveNameCallbacksPtr a_Callbacks
	);


	/** Queues a DNS query to resolve the specified IP address to a hostname.
	Calls one of the callbacks when the resolving succeeds, or when it fails.
	Returns true if queueing was successful, false if not.
	Note that the return value doesn't report the success of the actual lookup; the lookup happens asynchronously on the background. */
	bool IPToHostName(
		const AString & a_IP,
		cNetwork::cResolveNameCallbacksPtr a_Callbacks
	);

protected:

	/** The main LibEvent container for driving the event loop. */
	event_base * m_EventBase;

	/** The LibEvent handle for doing DNS lookups. */
	evdns_base * m_DNSBase;

	/** Container for all client connections, including ones with pending-connect. */
	cTCPLinkImplPtrs m_Connections;

	/** Container for all servers that are currently active. */
	cServerHandleImplPtrs m_Servers;

	/** Container for all pending hostname lookups. */
	cHostnameLookupPtrs m_HostnameLookups;

	/** Container for all pending IP lookups. */
	cIPLookupPtrs m_IPLookups;

	/** Mutex protecting all containers against multithreaded access. */
	cCriticalSection m_CS;


	/** Initializes the LibEvent internals. */
	cNetworkSingleton(void);

	/** Converts LibEvent-generated log events into log messages in MCS log. */
	static void LogCallback(int a_Severity, const char * a_Msg);

	/** Implements the thread that runs LibEvent's event dispatcher loop. */
	static void RunEventLoop(cNetworkSingleton * a_Self);

	/** Removes the specified hostname lookup from m_HostnameLookups.
	Used by the underlying lookup implementation when the lookup is finished. */
	void RemoveHostnameLookup(const cHostnameLookup * a_HostnameLookup);

	/** Removes the specified IP lookup from m_IPLookups.
	Used by the underlying lookup implementation when the lookup is finished. */
	void RemoveIPLookup(const cIPLookup * a_IPLookup);

	/** Removes the specified link from m_Connections.
	Used by the underlying link implementation when the link is closed / errored. */
	void RemoveLink(const cTCPLinkImpl * a_Link);
};





////////////////////////////////////////////////////////////////////////////////
// Globals:

bool IsValidSocket(evutil_socket_t a_Socket)
{
	#ifdef _WIN32
		return (a_Socket != INVALID_SOCKET);
	#else  // _WIN32
		return (a_Socket >= 0);
	#endif  // else _WIN32
}





////////////////////////////////////////////////////////////////////////////////
// cHostnameLookup:

cHostnameLookup::cHostnameLookup(const AString & a_Hostname, cNetwork::cResolveNameCallbacksPtr a_Callbacks):
	m_Callbacks(a_Callbacks),
	m_Hostname(a_Hostname)
{
	evutil_addrinfo hints;
	memset(&hints, 0, sizeof(hints));
	hints.ai_protocol = IPPROTO_TCP;
	hints.ai_socktype = SOCK_STREAM;
	hints.ai_family = AF_UNSPEC;
	hints.ai_flags = EVUTIL_AI_CANONNAME;
	evdns_getaddrinfo(cNetworkSingleton::Get().m_DNSBase, a_Hostname.c_str(), nullptr, &hints, Callback, this);
}





void cHostnameLookup::Callback(int a_ErrCode, evutil_addrinfo * a_Addr, void * a_Self)
{
	// Get the Self class:
	cHostnameLookup * Self = reinterpret_cast<cHostnameLookup *>(a_Self);
	ASSERT(Self != nullptr);

	// If an error has occurred, notify the error callback:
	if (a_ErrCode != 0)
	{
		Self->m_Callbacks->OnError(a_ErrCode);
		cNetworkSingleton::Get().RemoveHostnameLookup(Self);
		return;
	}

	// Call the success handler for each entry received:
	bool HasResolved = false;
	evutil_addrinfo * OrigAddr = a_Addr;
	for (;a_Addr != nullptr; a_Addr = a_Addr->ai_next)
	{
		char IP[128];
		switch (a_Addr->ai_family)
		{
			case AF_INET:  // IPv4
			{
				sockaddr_in * sin = reinterpret_cast<sockaddr_in *>(a_Addr->ai_addr);
				evutil_inet_ntop(AF_INET, &(sin->sin_addr), IP, sizeof(IP));
				break;
			}
			case AF_INET6:  // IPv6
			{
				sockaddr_in6 * sin = reinterpret_cast<sockaddr_in6 *>(a_Addr->ai_addr);
				evutil_inet_ntop(AF_INET6, &(sin->sin6_addr), IP, sizeof(IP));
				break;
			}
			default:
			{
				// Unknown address family, handle as if this entry wasn't received
				continue;  // for (a_Addr)
			}
		}
		Self->m_Callbacks->OnNameResolved(Self->m_Hostname, IP);
		HasResolved = true;
	}  // for (a_Addr)

	// If only unsupported families were reported, call the Error handler:
	if (!HasResolved)
	{
		Self->m_Callbacks->OnError(1);
	}
	else
	{
		Self->m_Callbacks->OnFinished();
	}
	evutil_freeaddrinfo(OrigAddr);
	cNetworkSingleton::Get().RemoveHostnameLookup(Self);
}





////////////////////////////////////////////////////////////////////////////////
// cIPLookup:

cIPLookup::cIPLookup(const AString & a_IP, cNetwork::cResolveNameCallbacksPtr a_Callbacks):
	m_Callbacks(a_Callbacks),
	m_IP(a_IP)
{
	sockaddr_storage sa;
	int salen = static_cast<int>(sizeof(sa));
	evutil_parse_sockaddr_port(a_IP.c_str(), reinterpret_cast<sockaddr *>(&sa), &salen);
	switch (sa.ss_family)
	{
		case AF_INET:
		{
			sockaddr_in * sa4 = reinterpret_cast<sockaddr_in *>(&sa);
			evdns_base_resolve_reverse(cNetworkSingleton::Get().m_DNSBase, &(sa4->sin_addr), 0, Callback, this);
			break;
		}
		case AF_INET6:
		{
			sockaddr_in6 * sa6 = reinterpret_cast<sockaddr_in6 *>(&sa);
			evdns_base_resolve_reverse_ipv6(cNetworkSingleton::Get().m_DNSBase, &(sa6->sin6_addr), 0, Callback, this);
			break;
		}
		default:
		{
			LOGWARNING("%s: Unknown address family: %d", __FUNCTION__, sa.ss_family);
			ASSERT(!"Unknown address family");
			break;
		}
	}  // switch (address family)
}





void cIPLookup::Callback(int a_Result, char a_Type, int a_Count, int a_Ttl, void * a_Addresses, void * a_Self)
{
	// Get the Self class:
	cIPLookup * Self = reinterpret_cast<cIPLookup *>(a_Self);
	ASSERT(Self != nullptr);

	if ((a_Result != 0) || (a_Addresses == nullptr))
	{
		// An error has occurred, notify the error callback:
		Self->m_Callbacks->OnError(a_Result);
	}
	else
	{
		// Call the success handler::
		Self->m_Callbacks->OnNameResolved(*(reinterpret_cast<char **>(a_Addresses)), Self->m_IP);
		Self->m_Callbacks->OnFinished();
	}
	cNetworkSingleton::Get().RemoveIPLookup(Self);
}





////////////////////////////////////////////////////////////////////////////////
// cTCPLinkImpl:

cTCPLinkImpl::cTCPLinkImpl(cTCPLink::cCallbacksPtr a_LinkCallbacks):
	super(a_LinkCallbacks),
	m_BufferEvent(bufferevent_socket_new(cNetworkSingleton::Get().m_EventBase, -1, BEV_OPT_CLOSE_ON_FREE)),
	m_Server(nullptr)
{
	bufferevent_setcb(m_BufferEvent, ReadCallback, nullptr, EventCallback, this);
	bufferevent_enable(m_BufferEvent, EV_READ | EV_WRITE);
}





cTCPLinkImpl::cTCPLinkImpl(evutil_socket_t a_Socket, cTCPLink::cCallbacksPtr a_LinkCallbacks, cServerHandleImpl * a_Server, const sockaddr * a_Address, int a_AddrLen):
	super(a_LinkCallbacks),
	m_BufferEvent(bufferevent_socket_new(cNetworkSingleton::Get().m_EventBase, a_Socket, BEV_OPT_CLOSE_ON_FREE)),
	m_Server(a_Server)
{
	UpdateLocalAddress();
	UpdateAddress(a_Address, a_AddrLen, m_RemoteIP, m_RemotePort);
	bufferevent_setcb(m_BufferEvent, ReadCallback, nullptr, EventCallback, this);
	bufferevent_enable(m_BufferEvent, EV_READ | EV_WRITE);
}





cTCPLinkImpl::~cTCPLinkImpl()
{
	bufferevent_free(m_BufferEvent);
}





/** Schedules the actual connection request.
Returns true on success, false on failure. */
bool cTCPLinkImpl::Connect(const AString & a_Host, UInt16 a_Port, cNetwork::cConnectCallbacksPtr a_ConnectCallbacks)
{
	ASSERT(bufferevent_getfd(m_BufferEvent) == -1);  // Did you create this object using the right constructor (the one without the Socket param)?
	ASSERT(m_Server == nullptr);
	ASSERT(a_ConnectCallbacks != nullptr);

	m_ConnectCallbacks = a_ConnectCallbacks;

	// If a_Host is an IP address, schedule a connection immediately:
	sockaddr_storage sa;
	int salen = static_cast<int>(sizeof(sa));
	if (evutil_parse_sockaddr_port(a_Host.c_str(), reinterpret_cast<sockaddr *>(&sa), &salen) == 0)
	{
		// Insert the correct port:
		if (sa.ss_family == AF_INET6)
		{
			reinterpret_cast<sockaddr_in6 *>(&sa)->sin6_port = htons(a_Port);
		}
		else
		{
			reinterpret_cast<sockaddr_in *>(&sa)->sin_port = htons(a_Port);
		}

		if (bufferevent_socket_connect(m_BufferEvent, reinterpret_cast<sockaddr *>(&sa), salen) == 0)
		{
			// Success
			return true;
		}
		// Failure
		return false;
	}

	// a_Host is a hostname, connect after a lookup:
	if (bufferevent_socket_connect_hostname(m_BufferEvent, cNetworkSingleton::Get().m_DNSBase, AF_UNSPEC, a_Host.c_str(), a_Port) == 0)
	{
		// Success
		return true;
	}
	// Failure
	return false;
}





bool cTCPLinkImpl::Send(const void * a_Data, size_t a_Length)
{
	return (bufferevent_write(m_BufferEvent, a_Data, a_Length) == 0);
}





void cTCPLinkImpl::Shutdown(void)
{
	#ifdef _WIN32
		shutdown(bufferevent_getfd(m_BufferEvent), SD_SEND);
	#else
		shutdown(bufferevent_getfd(m_BufferEvent), SHUT_WR);
	#endif
	bufferevent_disable(m_BufferEvent, EV_WRITE);
}





void cTCPLinkImpl::Close(void)
{
	// Disable all events on the socket, but keep it alive (multithreading):
	bufferevent_disable(m_BufferEvent, EV_READ | EV_WRITE);
	if (m_Server == nullptr)
	{
		cNetworkSingleton::Get().RemoveLink(this);
	}
	else
	{
		m_Server->RemoveLink(this);
	}
}






void cTCPLinkImpl::ReadCallback(bufferevent * a_BufferEvent, void * a_Self)
{
	ASSERT(a_Self != nullptr);
	cTCPLinkImpl * Self = static_cast<cTCPLinkImpl *>(a_Self);
	ASSERT(Self->m_Callbacks != nullptr);

	// Read all the incoming data, in 1024-byte chunks:
	char data[1024];
	size_t length;
	while ((length = bufferevent_read(a_BufferEvent, data, sizeof(data))) > 0)
	{
		Self->m_Callbacks->OnReceivedData(*Self, data, length);
	}
}





void cTCPLinkImpl::EventCallback(bufferevent * a_BufferEvent, short a_What, void * a_Self)
{
	ASSERT(a_Self != nullptr);
	cTCPLinkImpl * Self = static_cast<cTCPLinkImpl *>(a_Self);

	// If an error is reported, call the error callback:
	if (a_What & BEV_EVENT_ERROR)
	{
		// Choose the proper callback to call based on whether we were waiting for connection or not:
		if (Self->m_ConnectCallbacks != nullptr)
		{
			Self->m_ConnectCallbacks->OnError(EVUTIL_SOCKET_ERROR());
		}
		else
		{
			Self->m_Callbacks->OnError(*Self, EVUTIL_SOCKET_ERROR());
			if (Self->m_Server == nullptr)
			{
				cNetworkSingleton::Get().RemoveLink(Self);
			}
			else
			{
				Self->m_Server->RemoveLink(Self);
			}
		}
		return;
	}

	// Pending connection succeeded, call the connection callback:
	if (a_What & BEV_EVENT_CONNECTED)
	{
		if (Self->m_ConnectCallbacks != nullptr)
		{
			Self->m_ConnectCallbacks->OnSuccess(*Self);
			// Reset the connect callbacks so that later errors get reported through the link callbacks:
			Self->m_ConnectCallbacks.reset();
			return;
		}
		Self->UpdateLocalAddress();
		Self->UpdateRemoteAddress();
	}

	// If the connection has been closed, call the link callback and remove the connection:
	if (a_What & BEV_EVENT_EOF)
	{
		Self->m_Callbacks->OnRemoteClosed(*Self);
		if (Self->m_Server != nullptr)
		{
			Self->m_Server->RemoveLink(Self);
		}
		else
		{
			cNetworkSingleton::Get().RemoveLink(Self);
		}
		return;
	}
	
	// Unknown event, report it:
	LOGWARNING("cTCPLinkImpl: Unhandled LibEvent event %d (0x%x)", a_What, a_What);
	ASSERT(!"cTCPLinkImpl: Unhandled LibEvent event");
}





void cTCPLinkImpl::UpdateAddress(const sockaddr * a_Address, int a_AddrLen, AString & a_IP, UInt16 & a_Port)
{
	char IP[128];
	switch (a_Address->sa_family)
	{
		case AF_INET:  // IPv4:
		{
			const sockaddr_in * sin = reinterpret_cast<const sockaddr_in *>(a_Address);
			evutil_inet_ntop(AF_INET, &(sin->sin_addr), IP, sizeof(IP));
			a_Port = ntohs(sin->sin_port);
			break;
		}
		case AF_INET6:  // IPv6
		{
			const sockaddr_in6 * sin = reinterpret_cast<const sockaddr_in6 *>(a_Address);
			evutil_inet_ntop(AF_INET6, &(sin->sin6_addr), IP, sizeof(IP));
			a_Port = ntohs(sin->sin6_port);
			break;
		}

		default:
		{
			LOGWARNING("%s: Unknown socket address family: %d", __FUNCTION__, a_Address->sa_family);
			ASSERT(!"Unknown socket address family");
			break;
		}
	}
	a_IP.assign(IP);
}





void cTCPLinkImpl::UpdateLocalAddress(void)
{
	sockaddr_storage sa;
	socklen_t salen = static_cast<socklen_t>(sizeof(sa));
	getsockname(bufferevent_getfd(m_BufferEvent), reinterpret_cast<sockaddr *>(&sa), &salen);
	UpdateAddress(reinterpret_cast<const sockaddr *>(&sa), salen, m_LocalIP, m_LocalPort);
}





void cTCPLinkImpl::UpdateRemoteAddress(void)
{
	sockaddr_storage sa;
	socklen_t salen = static_cast<socklen_t>(sizeof(sa));
	getpeername(bufferevent_getfd(m_BufferEvent), reinterpret_cast<sockaddr *>(&sa), &salen);
	UpdateAddress(reinterpret_cast<const sockaddr *>(&sa), salen, m_LocalIP, m_LocalPort);
}





////////////////////////////////////////////////////////////////////////////////
// cServerHandleImpl:

cServerHandleImpl::cServerHandleImpl(cNetwork::cListenCallbacksPtr a_ListenCallbacks, cTCPLink::cCallbacksPtr a_LinkCallbacks):
	m_ListenCallbacks(a_ListenCallbacks),
	m_LinkCallbacks(a_LinkCallbacks),
	m_ConnListener(nullptr),
	m_SecondaryConnListener(nullptr),
	m_IsListening(false)
{
}





cServerHandleImpl::~cServerHandleImpl()
{
	if (m_ConnListener != nullptr)
	{
		evconnlistener_free(m_ConnListener);
	}
	if (m_SecondaryConnListener != nullptr)
	{
		evconnlistener_free(m_SecondaryConnListener);
	}
}





void cServerHandleImpl::Close(void)
{
	// Stop the listener sockets:
	evconnlistener_disable(m_ConnListener);
	if (m_SecondaryConnListener != nullptr)
	{
		evconnlistener_disable(m_SecondaryConnListener);
	}
	m_IsListening = false;

	// Shutdown all connections:
	cTCPLinkImplPtrs Conns;
	{
		cCSLock Lock(m_CS);
		std::swap(Conns, m_Connections);
	}
	for (auto conn: Conns)
	{
		conn->Shutdown();
	}
}





bool cServerHandleImpl::Listen(UInt16 a_Port)
{
	ASSERT(!m_IsListening);

	// Set up the main socket:
	// It should listen on IPv6 with IPv4 fallback, when available; IPv4 when IPv6 is not available.
	bool NeedsTwoSockets = false;
	evutil_socket_t MainSock = socket(AF_INET6, SOCK_STREAM, IPPROTO_TCP);
	if (!IsValidSocket(MainSock))
	{
		// Failed to create IPv6 socket, create an IPv4 one instead:
		int err = EVUTIL_SOCKET_ERROR();
		LOGD("Failed to create IPv6 MainSock: %d (%s)", err, evutil_socket_error_to_string(err));
		MainSock = socket(AF_INET, SOCK_STREAM, IPPROTO_TCP);
		if (!IsValidSocket(MainSock))
		{
			int err = EVUTIL_SOCKET_ERROR();
			LOGWARNING("%s: Cannot create a socket for neither IPv6 nor IPv4: %d (%s)", __FUNCTION__, err, evutil_socket_error_to_string(err));
			return false;
		}

		// Bind to all interfaces:
		sockaddr_in name;
		memset(&name, 0, sizeof(name));
		name.sin_family = AF_INET;
		name.sin_port = ntohs(a_Port);
		if (bind(MainSock, reinterpret_cast<const sockaddr *>(&name), sizeof(name)) != 0)
		{
			int err = EVUTIL_SOCKET_ERROR();
			LOGWARNING("Cannot bind to IPv4 port %d: %d (%s)", a_Port, err, evutil_socket_error_to_string(err));
			evutil_closesocket(MainSock);
			return false;
		}
	}
	else
	{
		// IPv6 socket created, switch it into "dualstack" mode:
		UInt32 Zero = 0;
		#ifdef _WIN32
			// WinXP doesn't support this feature, so if the setting fails, create another socket later on:
			int res = setsockopt(MainSock, IPPROTO_IPV6, IPV6_V6ONLY, reinterpret_cast<const char *>(&Zero), sizeof(Zero));
			int err = EVUTIL_SOCKET_ERROR();
			NeedsTwoSockets = ((res == SOCKET_ERROR) && (err == WSAENOPROTOOPT));
			LOGD("setsockopt(IPV6_V6ONLY) returned %d, err is %d (%s). %s",
				res, err, evutil_socket_error_to_string(err),
				NeedsTwoSockets ? "Second socket will be created" : "Second socket not needed"
			);
		#else
			setsockopt(MainSock, IPPROTO_IPV6, IPV6_V6ONLY, reinterpret_cast<const char *>(&Zero), sizeof(Zero));
		#endif

		// Bind to all interfaces:
		sockaddr_in6 name;
		memset(&name, 0, sizeof(name));
		name.sin6_family = AF_INET6;
		name.sin6_port = ntohs(a_Port);
		if (bind(MainSock, reinterpret_cast<const sockaddr *>(&name), sizeof(name)) != 0)
		{
			int err = EVUTIL_SOCKET_ERROR();
			LOGWARNING("Cannot bind to IPv6 port %d: %d (%s)", a_Port, err, evutil_socket_error_to_string(err));
			evutil_closesocket(MainSock);
			return false;
		}
	}
	if (evutil_make_socket_nonblocking(MainSock) != 0)
	{
		int err = EVUTIL_SOCKET_ERROR();
		LOGWARNING("Cannot make socket for port %d non-blocking: %d (%s)", a_Port, err, evutil_socket_error_to_string(err));
		evutil_closesocket(MainSock);
		return false;
	}
	if (listen(MainSock, 0) != 0)
	{
		int err = EVUTIL_SOCKET_ERROR();
		LOGWARNING("Cannot listen on port %d: %d (%s)", a_Port, err, evutil_socket_error_to_string(err));
		evutil_closesocket(MainSock);
		return false;
	}
	m_ConnListener = evconnlistener_new(cNetworkSingleton::Get().m_EventBase, Callback, this, LEV_OPT_CLOSE_ON_FREE | LEV_OPT_REUSEABLE, 0, MainSock);

	// If a secondary socket is required (WinXP dual-stack), create it here:
	if (NeedsTwoSockets)
	{
		LOGD("Creating a second socket for IPv4");
		evutil_socket_t SecondSock = socket(AF_INET, SOCK_STREAM, IPPROTO_TCP);
		if (IsValidSocket(SecondSock))
		{
			if (evutil_make_socket_nonblocking(SecondSock) == 0)
			{
				m_SecondaryConnListener = evconnlistener_new(cNetworkSingleton::Get().m_EventBase, Callback, this, LEV_OPT_CLOSE_ON_FREE | LEV_OPT_REUSEABLE, 0, SecondSock);
			}
			else
			{
				int err = EVUTIL_SOCKET_ERROR();
				LOGD("evutil_make_socket_nonblocking() failed: %d, %s", err, evutil_socket_error_to_string(err));
			}
		}
		else
		{
			int err = EVUTIL_SOCKET_ERROR();
			LOGD("socket(AF_INET, ...) failed: %d, %s", err, evutil_socket_error_to_string(err));
		}
	}
	m_IsListening = true;
	return true;
}





void cServerHandleImpl::Callback(evconnlistener * a_Listener, evutil_socket_t a_Socket, sockaddr * a_Addr, int a_Len, void * a_Self)
{
	// Cast to true self:
	cServerHandleImpl * Self = reinterpret_cast<cServerHandleImpl *>(a_Self);
	ASSERT(Self != nullptr);

	// Create a new cTCPLink for the incoming connection:
	cTCPLinkImplPtr Link = std::make_shared<cTCPLinkImpl>(a_Socket, Self->m_LinkCallbacks, Self, a_Addr, a_Len);
	{
		cCSLock Lock(Self->m_CS);
		Self->m_Connections.push_back(Link);
	}  // Lock(m_CS)

	// Call the OnAccepted callback:
	Self->m_ListenCallbacks->OnAccepted(*Link);
}





void cServerHandleImpl::RemoveLink(const cTCPLinkImpl * a_Link)
{
	cCSLock Lock(m_CS);
	for (auto itr = m_Connections.begin(), end = m_Connections.end(); itr != end; ++itr)
	{
		if (itr->get() == a_Link)
		{
			m_Connections.erase(itr);
			return;
		}
	}  // for itr - m_Connections[]
}





////////////////////////////////////////////////////////////////////////////////
// cNetwork:

bool cNetwork::Connect(
	const AString & a_Host,
	const UInt16 a_Port,
	cNetwork::cConnectCallbacksPtr a_ConnectCallbacks,
	cTCPLink::cCallbacksPtr a_LinkCallbacks
)
{
	return cNetworkSingleton::Get().Connect(a_Host, a_Port, a_ConnectCallbacks, a_LinkCallbacks);
}





cServerHandlePtr cNetwork::Listen(
	const UInt16 a_Port,
	cNetwork::cListenCallbacksPtr a_ListenCallbacks,
	cTCPLink::cCallbacksPtr a_LinkCallbacks
)
{
	return cNetworkSingleton::Get().Listen(a_Port, a_ListenCallbacks, a_LinkCallbacks);
}





bool cNetwork::HostnameToIP(
	const AString & a_Hostname,
	cNetwork::cResolveNameCallbacksPtr a_Callbacks
)
{
	return cNetworkSingleton::Get().HostnameToIP(a_Hostname, a_Callbacks);
}





bool cNetwork::IPToHostName(
	const AString & a_IP,
	cNetwork::cResolveNameCallbacksPtr a_Callbacks
)
{
	return cNetworkSingleton::Get().IPToHostName(a_IP, a_Callbacks);
}




////////////////////////////////////////////////////////////////////////////////
// cTCPLink:

cTCPLink::cTCPLink(cCallbacksPtr a_Callbacks):
	m_Callbacks(a_Callbacks)
{
}




////////////////////////////////////////////////////////////////////////////////
// cNetworkSingleton:

cNetworkSingleton::cNetworkSingleton(void)
{
	// Windows: initialize networking:
	#ifdef _WIN32
		WSADATA wsaData;
		memset(&wsaData, 0, sizeof(wsaData));
		WSAStartup (MAKEWORD(2, 2), &wsaData);
	#endif  // _WIN32

	// Initialize LibEvent logging:
	event_set_log_callback(LogCallback);

	// Initialize threading:
	#if defined(EVTHREAD_USE_WINDOWS_THREADS_IMPLEMENTED)
		evthread_use_windows_threads();
	#elif defined(EVTHREAD_USE_PTHREADS_IMPLEMENTED)
		evthread_use_pthreads();
	#else
		#error No threading implemented for EVTHREAD
	#endif

	// Create the main event_base:
	m_EventBase = event_base_new();
	if (m_EventBase == nullptr)
	{
		LOGERROR("Failed to initialize LibEvent. The server will now terminate.");
		abort();
	}

	// Create the DNS lookup helper:
	m_DNSBase = evdns_base_new(m_EventBase, 1);
	if (m_DNSBase == nullptr)
	{
		LOGERROR("Failed to initialize LibEvent's DNS subsystem. The server will now terminate.");
		abort();
	}

	// Create the event loop thread:
	std::thread EventLoopThread(RunEventLoop, this);
	EventLoopThread.detach();
}





cNetworkSingleton & cNetworkSingleton::Get(void)
{
	static cNetworkSingleton Instance;
	return Instance;
}





bool cNetworkSingleton::Connect(
	const AString & a_Host,
	const UInt16 a_Port,
	cNetwork::cConnectCallbacksPtr a_ConnectCallbacks,
	cTCPLink::cCallbacksPtr a_LinkCallbacks
)
{
	// Add a connection request to the queue:
	cTCPLinkImplPtr ConnRequest = std::make_shared<cTCPLinkImpl>(a_LinkCallbacks);
	{
		cCSLock Lock(m_CS);
		m_Connections.push_back(ConnRequest);
	}  // Lock(m_CS)

	// Queue the connection:
	if (!ConnRequest->Connect(a_Host, a_Port, a_ConnectCallbacks))
	{
		RemoveLink(ConnRequest.get());
		return false;
	}

	// Everything successful, return success:
	return true;
}





cServerHandlePtr cNetworkSingleton::Listen(
	const UInt16 a_Port,
	cNetwork::cListenCallbacksPtr a_ListenCallbacks,
	cTCPLink::cCallbacksPtr a_LinkCallbacks
)
{
	cServerHandleImplPtr res = std::make_shared<cServerHandleImpl>(a_ListenCallbacks, a_LinkCallbacks);
	if (!res->Listen(a_Port))
	{
		return res;
	}
	cCSLock Lock(m_CS);
	m_Servers.push_back(res);
	return res;
}





bool cNetworkSingleton::HostnameToIP(
	const AString & a_Hostname,
	cNetwork::cResolveNameCallbacksPtr a_Callbacks
)
{
	try
	{
		cCSLock Lock(m_CS);
		m_HostnameLookups.push_back(std::make_shared<cHostnameLookup>(a_Hostname, a_Callbacks));
	}
	catch (...)
	{
		return false;
	}
	return true;
}




bool cNetworkSingleton::IPToHostName(
	const AString & a_IP,
	cNetwork::cResolveNameCallbacksPtr a_Callbacks
)
{
	try
	{
		cCSLock Lock(m_CS);
		m_IPLookups.push_back(std::make_shared<cIPLookup>(a_IP, a_Callbacks));
	}
	catch (...)
	{
		return false;
	}
	return true;
}




void cNetworkSingleton::LogCallback(int a_Severity, const char * a_Msg)
{
	switch (a_Severity)
	{
		case _EVENT_LOG_DEBUG: LOGD      ("LibEvent: %s", a_Msg); break;
		case _EVENT_LOG_MSG:   LOG       ("LibEvent: %s", a_Msg); break;
		case _EVENT_LOG_WARN:  LOGWARNING("LibEvent: %s", a_Msg); break;
		case _EVENT_LOG_ERR:   LOGERROR  ("LibEvent: %s", a_Msg); break;
		default:
		{
			printf("LibEvent: %s", a_Msg);
			break;
		}
	}
}





void cNetworkSingleton::RunEventLoop(cNetworkSingleton * a_Self)
{
	event_base_loop(a_Self->m_EventBase, EVLOOP_NO_EXIT_ON_EMPTY);
}





void cNetworkSingleton::RemoveHostnameLookup(const cHostnameLookup * a_HostnameLookup)
{
	cCSLock Lock(m_CS);
	for (auto itr = m_HostnameLookups.begin(), end = m_HostnameLookups.end(); itr != end; ++itr)
	{
		if (itr->get() == a_HostnameLookup)
		{
			m_HostnameLookups.erase(itr);
			return;
		}
	}  // for itr - m_HostnameLookups[]
}





void cNetworkSingleton::RemoveIPLookup(const cIPLookup * a_IPLookup)
{
	cCSLock Lock(m_CS);
	for (auto itr = m_IPLookups.begin(), end = m_IPLookups.end(); itr != end; ++itr)
	{
		if (itr->get() == a_IPLookup)
		{
			m_IPLookups.erase(itr);
			return;
		}
	}  // for itr - m_IPLookups[]
}





void cNetworkSingleton::RemoveLink(const cTCPLinkImpl * a_Link)
{
	cCSLock Lock(m_CS);
	for (auto itr = m_Connections.begin(), end = m_Connections.end(); itr != end; ++itr)
	{
		if (itr->get() == a_Link)
		{
			m_Connections.erase(itr);
			return;
		}
	}  // for itr - m_Connections[]
}